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An ionic bond forms when atoms of a nonmetal give up electrons to atoms of a metal. | (A) true (B) false | B | An ionic bond is the force of attraction that holds together positive and negative ions. It forms when atoms of a metallic element give up electrons to atoms of a nonmetallic element. The Figure 1.1 shows how this happens. In row 1 of the Figure 1.1, an atom of sodium (Na) donates an electron to an atom of chlorine (Cl... |
Sodium and chloride ions have equal but opposite charges. | (A) true (B) false | A | An ionic bond is the force of attraction that holds together positive and negative ions. It forms when atoms of a metallic element give up electrons to atoms of a nonmetallic element. Figure 7.3 shows how this happens. In row 1 of Figure 7.3, an atom of sodium donates an electron to an atom of chlorine (Cl). By losing ... |
Metals need energy in order to become ions. | (A) true (B) false | A | It takes energy to remove valence electrons from an atom. The force of attraction between the negative electrons and positive nucleus must be overcome. The amount of energy needed depends on the element. Less energy is needed to remove just one or a few electrons than many. This explains why sodium and other alkali met... |
The bonds of crystals are very weak. | (A) true (B) false | B | Different types of minerals break apart in their own way. Remember that all minerals are crystals. This means that the atoms in a mineral are arranged in a repeating pattern. This pattern determines how a mineral will break. When you break a mineral, you break chemical bonds. Because of the way the atoms are arranged, ... |
Solid ionic compounds are good conductors of electricity. | (A) true (B) false | B | The crystal structure of ionic compounds is strong and rigid. It takes a lot of energy to break all those strong ionic bonds. As a result, ionic compounds are solids with high melting and boiling points (see Table 7.2). The rigid crystals are brittle and more likely to break than bend when struck. As a result, ionic cr... |
dissolved ionic compound | (A) ion (B) ionic bond (C) ionic compound (D) crystal (E) electrolyte (F) sodium (G) chloride | E | The crystal structure of ionic compounds is strong and rigid. It takes a lot of energy to break all those ionic bonds. As a result, ionic compounds are solids with high melting and boiling points. You can see the melting and boiling points of several different ionic compounds in the Table 1.1. To appreciate how high th... |
unique substance that forms when a metal and a nonmetal combine chemically | (A) ion (B) ionic bond (C) ionic compound (D) crystal (E) electrolyte (F) sodium (G) chloride | C | There are millions of different substances in the world. Thats because elements can combine in many different ways to form new substances. In fact, most elements are found in compounds. A compound is a unique substance that forms when two or more elements combine chemically. An example is water, which forms when hydrog... |
example of an alkali metal | (A) ion (B) ionic bond (C) ionic compound (D) crystal (E) electrolyte (F) sodium (G) chloride | F | Besides being very reactive, alkali metals share a number of other properties. Alkali metals are all solids at room temperature. Alkali metals are low in density, and some of them float on water. Alkali metals are relatively soft. Some are even soft enough to cut with a knife, like the sodium pictured in the Figure 1.1... |
force of attraction that holds together positive and negative ions | (A) ion (B) ionic bond (C) ionic compound (D) crystal (E) electrolyte (F) sodium (G) chloride | B | When it comes to electric charges, opposites attract, so positive and negative particles attract each other. You can see this in the Figure 1.2. This attraction explains why negative electrons keep moving around the positive nucleus of the atom. Like charges, on the other hand, repel each other, so two positive or two ... |
example of a negative ion | (A) ion (B) ionic bond (C) ionic compound (D) crystal (E) electrolyte (F) sodium (G) chloride | G | Sometimes atoms lose or gain electrons. Then they become ions. Ions have a positive or negative charge. Thats because they do not have the same number of electrons as protons. If atoms lose electrons, they become positive ions, or cations. If atoms gain electrons, they become negative ions, or anions. Consider the exam... |
charged particle that forms when an atom gains or loses electrons | (A) ion (B) ionic bond (C) ionic compound (D) crystal (E) electrolyte (F) sodium (G) chloride | A | The girl pictured above became negatively charged because electrons flowed from the van de Graaff generator to her. Whenever electrons are transferred between objects, neutral matter becomes charged. This occurs even with individual atoms. Atoms are neutral in electric charge because they have the same number of negati... |
structure that forms when many positive and negative ions bond together | (A) ion (B) ionic bond (C) ionic compound (D) crystal (E) electrolyte (F) sodium (G) chloride | D | Ions come together to create a molecule so that electrical charges are balanced; the positive charges balance the negative charges and the molecule has no electrical charge. To balance electrical charge, an atom may share its electron with another atom, give it away, or receive an electron from another atom. The joinin... |
When metallic elements become ions they | (A) gain electrons (B) become positively charged (C) become negatively charged (D) two of the above | B | Atoms cannot only gain extra electrons. They can also lose electrons. In either case, they become ions. Ions are atoms that have a positive or negative charge because they have unequal numbers of protons and electrons. If atoms lose electrons, they become positive ions, or cations. If atoms gain electrons, they become ... |
Which two elements could form an ionic compound? | (A) carbon and oxygen (B) hydrogen and nitrogen (C) lithium and fluorine (D) boron and neon | C | All compounds form when atoms of different elements share or transfer electrons. Compounds in which electrons are transferred from one atom to another are called ionic compounds. In this type of compound, electrons actually move between the atoms, rather than being shared between them. When atoms give up or accept elec... |
Which statement about energy and ionic bonds is true? | (A) It takes energy to form a negative ion (B) Halogens need the most energy to become ions (C) It takes energy to remove valence electrons from an atom (D) It takes more energy to gain two electrons than one electron | C | All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. In some chemical reactions, called exothermic reactions, more energy is released when new bonds form in the products than is needed to break bonds in the reactants. The opposite is ... |
Which of the following compounds is not an ionic compound? | (A) barium oxide (B) lithium oxide (C) carbon dioxide (D) calcium chloride | C | The Table 1.1 shows four examples of compounds and their chemical formulas. The first two compounds are ionic compounds, and the second two are covalent compounds. Each formula shows the ratio of ions or atoms that make up the compound. Name of Compound Type of Compound Sodium chloride ionic Calcium iodide ionic Hydrog... |
Properties of ionic compounds include | (A) high melting points (B) high boiling points (C) brittleness (D) all of the above | D | The crystal structure of ionic compounds is strong and rigid. It takes a lot of energy to break all those strong ionic bonds. As a result, ionic compounds are solids with high melting and boiling points (see Table 7.2). The rigid crystals are brittle and more likely to break than bend when struck. As a result, ionic cr... |
Ionic compounds are good conductors of electricity when they are | (A) shaped into wires (B) dissolved in water (C) formed into crystals (D) made of two metals | B | Ionic compounds contain ions of metals and nonmetals held together by ionic bonds. Ionic compounds do not form molecules. Instead, many positive and negative ions bond together to form a structure called a crystal. You can see an example of a crystal in Figure 7.5. It shows the ionic compound sodium chloride. Positive ... |
In which of the following elements is the valence electron farthest from the nucleus? | (A) lithium (Li) (B) sodium (Na) (C) potassium (K) (D) rubidium (Rb) | D | Valence electrons are the electrons in the outer energy level of an atom that can participate in interactions with other atoms. Valence electrons are generally the electrons that are farthest from the nucleus. As a result, they may be attracted as much or more by the nucleus of another atom than they are by their own n... |
any compound consisting of two or more nonmetals | (A) covalent bond (B) hydrogen bond (C) polar bond (D) nonpolar bond (E) diatomic bond (F) polar compound (G) covalent compound | G | Compounds that form from two or more nonmetallic elements, such as carbon and hydrogen, are called covalent compounds. In a covalent compound, atoms of the different elements are held together in molecules by covalent bonds. These are chemical bonds in which atoms share valence electrons. The force of attraction betwee... |
Two hydrogen atoms may bond together to form a hydrogen | (A) ion (B) molecule (C) compound (D) two of the above | B | Covalent bonds form because they give atoms a more stable arrangement of electrons. Look at the hydrogen atoms in Figure 7.7. Alone, each hydrogen atom has just one electron. By sharing electrons with another hydrogen atom, it has two electrons: its own and the one in the other hydrogen atom. The shared electrons are a... |
covalent bond in which neither atom has an electric charge | (A) covalent bond (B) hydrogen bond (C) polar bond (D) nonpolar bond (E) diatomic bond (F) polar compound (G) covalent compound | D | Covalent bonds are chemical bonds between atoms of nonmetals that share valence electrons. In some covalent bonds, electrons are not shared equally between the two atoms. These are called polar covalent bonds. The Figure than the hydrogen atoms do because the nucleus of the oxygen atom has more positively charged proto... |
An example of a covalent compound is | (A) sodium fluoride (B) calcium chloride (C) carbon dioxide (D) all of the above | C | Compounds that form from two or more nonmetallic elements, such as carbon and hydrogen, are called covalent compounds. In a covalent compound, atoms of the different elements are held together in molecules by covalent bonds. These are chemical bonds in which atoms share valence electrons. The force of attraction betwee... |
covalent bond between two atoms of the same element | (A) covalent bond (B) hydrogen bond (C) polar bond (D) nonpolar bond (E) diatomic bond (F) polar compound (G) covalent compound | E | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
In all covalent bonds, valence electrons are | (A) lost (B) gained (C) shared equally (D) shared | D | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
The compound that contains two oxygen atoms and one nitrogen atom is named | (A) oxygen nitride (B) dioxygen nitride (C) nitrogen dioxide (D) nitrogen monoxide | C | To name simple covalent compounds, follow these rules: Start with the name of the element closer to the left side of the periodic table. Follow this with the name of element closer to the right of the periodic table. Give this second name the suffix -ide. Use prefixes to represent the numbers of the different atoms in ... |
force of attraction holding together two atoms that share a pair of electrons | (A) covalent bond (B) hydrogen bond (C) polar bond (D) nonpolar bond (E) diatomic bond (F) polar compound (G) covalent compound | A | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
weak bond that forms between oppositely charged ends of two molecules | (A) covalent bond (B) hydrogen bond (C) polar bond (D) nonpolar bond (E) diatomic bond (F) polar compound (G) covalent compound | B | Because of waters polarity, individual water molecules are attracted to one another. You can see this in the Figure of a nearby water molecule. This force of attraction is called a hydrogen bond. Hydrogen bonds are intermolecular (between-molecule) bonds, rather than intramolecular (within-molecule) bonds. They occur n... |
What is the chemical formula for the compound in question 4? | (A) O2 N (B) N2 O (C) NO (D) NO2 | D | Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no ... |
covalent bond in which the two atoms are oppositely charged | (A) covalent bond (B) hydrogen bond (C) polar bond (D) nonpolar bond (E) diatomic bond (F) polar compound (G) covalent compound | C | Covalent bonds are chemical bonds between atoms of nonmetals that share valence electrons. In some covalent bonds, electrons are not shared equally between the two atoms. These are called polar covalent bonds. The Figure than the hydrogen atoms do because the nucleus of the oxygen atom has more positively charged proto... |
compound in which molecules have oppositely charged ends | (A) covalent bond (B) hydrogen bond (C) polar bond (D) nonpolar bond (E) diatomic bond (F) polar compound (G) covalent compound | F | Polar compounds, such as water, are compounds that have a partial negative charge on one side of each molecule and a partial positive charge on the other side. All polar compounds contain polar bonds (although not all compounds that contain polar bonds are polar.) In a polar bond, two atoms share electrons unequally. O... |
Covalent bonds form only between atoms of different elements. | (A) true (B) false | B | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
A single covalent bond involves just one valence electron. | (A) true (B) false | B | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
Sharing electrons allows atoms to have a full outer energy level. | (A) true (B) false | A | To understand why chemical bonds form, consider the common compound known as water, or H2 O. It consists of two hydrogen (H) atoms and one oxygen (O) atom. As you can see in the on the left side of the Figure 1.1, each hydrogen atom has just one electron, which is also its sole valence electron. The oxygen atom has six... |
Each hydrogen atom can form two covalent bonds. | (A) true (B) false | B | Covalent bonds form because they give atoms a more stable arrangement of electrons. Look at the hydrogen atoms in Figure 7.7. Alone, each hydrogen atom has just one electron. By sharing electrons with another hydrogen atom, it has two electrons: its own and the one in the other hydrogen atom. The shared electrons are a... |
The hydrogen end of a water molecule is slightly negative in charge. | (A) true (B) false | B | Water is simply two atoms of hydrogen and one atom of oxygen bonded together (Figure 1.1). The hydrogen ions are on one side of the oxygen ion, making water a polar molecule. This means that one side, the side with the hydrogen ions, has a slightly positive electrical charge. The other side, the side without the hydrog... |
Covalent bonds are found only in covalent compounds. | (A) true (B) false | B | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
Some covalent compounds contain atoms of just one element. | (A) true (B) false | B | Compounds that form from two or more nonmetallic elements, such as carbon and hydrogen, are called covalent compounds. In a covalent compound, atoms of the different elements are held together in molecules by covalent bonds. These are chemical bonds in which atoms share valence electrons. The force of attraction betwee... |
Formaldehyde is an example of a covalent compound. | (A) true (B) false | A | Compounds that form from two or more nonmetallic elements, such as carbon and hydrogen, are called covalent compounds. In a covalent compound, atoms of the different elements are held together in molecules by covalent bonds. These are chemical bonds in which atoms share valence electrons. The force of attraction betwee... |
Oxygen gas consists of individual oxygen atoms. | (A) true (B) false | B | Figure 15.3 shows the main gases in air. Nitrogen and oxygen make up 99 percent of air. Argon and carbon dioxide make up much of the rest. These percentages are the same just about everywhere in the atmosphere. Air also includes water vapor. The amount of water vapor varies from place to place. Thats why water vapor is... |
An oxygen atom forms two covalent bonds. | (A) true (B) false | A | Covalent bonds form because they give atoms a more stable arrangement of electrons. Look at the oxygen atoms in the Figure 1.2. Alone, each oxygen atom has six valence electrons. By sharing two pairs of valence electrons, each oxygen atom has a total of eight valence electrons. This fills its outer energy level, giving... |
Oxygen always becomes negatively charged when it forms covalent bonds. | (A) true (B) false | B | Covalent bonds form because they give atoms a more stable arrangement of electrons. Look at the oxygen atoms in the Figure 1.2. Alone, each oxygen atom has six valence electrons. By sharing two pairs of valence electrons, each oxygen atom has a total of eight valence electrons. This fills its outer energy level, giving... |
In naming a covalent compound, the element closest to the right of the periodic table is named first. | (A) true (B) false | B | To name simple covalent compounds, follow these rules: Start with the name of the element closer to the left side of the periodic table. Follow this with the name of element closer to the right of the periodic table. Give this second name the suffix -ide. Use prefixes to represent the numbers of the different atoms in ... |
The second element named in a covalent compound gets the suffix ide. | (A) true (B) false | A | To name simple covalent compounds, follow these rules: Start with the name of the element closer to the left side of the periodic table. Follow this with the name of element closer to the right of the periodic table. Give this second name the suffix -ide. Use prefixes to represent the numbers of the different atoms in ... |
Polar compounds tend to have higher boiling points than nonpolar compounds. | (A) true (B) false | A | Changes of state from solid to liquid and from liquid to gas occur when matter gains energy. The energy allows individual molecules to separate and move apart from one another. It takes more energy to bring about these changes of state for polar molecules. Although hydrogen bonds are weak, they add to the energy needed... |
If a bond forms between calcium and chlorine, the bond is covalent. | (A) true (B) false | B | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
Covalent bonds may form between | (A) atoms of different elements (B) atoms of the same element (C) ions of different elements (D) two of the above | D | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
Elements that normally occur as diatomic molecules include | (A) hydrogen (B) iodine (C) oxygen (D) all of the above | D | The halogen group is quite diverse. It includes elements that occur in three different states of matter at room temperature. Fluorine and chlorine are gases, bromine is a liquid, and iodine and astatine are solids. Halogens also vary in color, as you can see in the Figure 1.2. Fluorine and chlorine are green, bromine i... |
Shared electrons in covalent bonds are always attracted to | (A) both nuclei (B) both nuclei equally (C) one nucleus more than the other (D) one nucleus only | A | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
How many covalent bonds must a hydrogen atom form to have a full outer energy level? | (A) 0 (B) 1 (C) 2 (D) 3 | B | To understand why chemical bonds form, consider the common compound known as water, or H2 O. It consists of two hydrogen (H) atoms and one oxygen (O) atom. As you can see in the on the left side of the Figure 1.1, each hydrogen atom has just one electron, which is also its sole valence electron. The oxygen atom has six... |
An example of a polar molecule is | (A) H2 O (B) CO2 (C) O2 (D) H2 | A | Polar compounds, such as water, are compounds that have a partial negative charge on one side of each molecule and a partial positive charge on the other side. All polar compounds contain polar bonds (although not all compounds that contain polar bonds are polar.) In a polar bond, two atoms share electrons unequally. O... |
Which statement about hydrogen bonds is true? | (A) They are very strong (B) They form between molecules (C) They form within molecules (D) two of the above | B | Because of waters polarity, individual water molecules are attracted to one another. You can see this in the Figure of a nearby water molecule. This force of attraction is called a hydrogen bond. Hydrogen bonds are intermolecular (between-molecule) bonds, rather than intramolecular (within-molecule) bonds. They occur n... |
Compared with ionic compounds, covalent compounds | (A) have lower melting points (B) have higher boiling points (C) are better conductors of electricity (D) are more likely to dissolve in water | A | Covalent compounds have different properties than ionic compounds because of their bonds. Covalent compounds exist as individual molecules rather than crystals. It takes less energy for individual molecules than ions in a crystal to pull apart. As a result, covalent compounds have lower melting and boiling points than ... |
Metallic bonds form because metals | (A) want to give up valence electrons (B) always share valence electrons (C) have many valence electrons (D) always gain valence electrons | A | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
Which statement about metallic bonds is true? | (A) They form between metals and nonmetals (B) They form between negative and positive ions (C) They form a lattice-like structure (D) two of the above | C | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
Which statement is true about all metals? | (A) They have one valence electron (B) They have freely moving electrons (C) They have more electrons than protons (D) They always gain electrons | B | Elements in the same class share certain basic similarities. In addition to conducting electricity, many metals have several other shared properties, including those listed below. Metals have relatively high melting points. This explains why all metals except for mercury are solids at room temperature. Most metals are ... |
In metallic bonds, the force of attraction is between | (A) positive and negative ions (B) ions and electrons (C) two different metals (D) neutrons and electrons | B | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
Because of metallic bonds, metals | (A) are good conductors of electricity (B) can change shape without breaking (C) are ductile and malleable (D) all of the above | D | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
Metals are used to make electric wires because metals | (A) are ductile (B) are malleable (C) have freely moving electrons (D) two of the above | D | Materials that have low resistance to electric current are called electric conductors. Many metalsincluding copper, aluminum, and steelare good conductors of electricity. The outer electrons of metal atoms are loosely bound and free to move, allowing electric current to flow. Water that has even a tiny amount of impuri... |
How does a metallic lattice differ from an ionic crystal? | (A) A metallic lattice is less flexible (B) A metallic lattice can change shape without breaking (C) A metallic lattice shatters when struck (D) all of the above | B | The valence electrons surrounding metal ions are constantly moving. This makes metals good conductors of electricity. The lattice-like structure of metal ions is strong but quite flexible. This allows metals to bend without breaking. Metals are both ductile (can be shaped into wires) and malleable (can be shaped into t... |
An alloy is a | (A) pure metal (B) compound of two or more metals (C) solid solution (D) mixture of nonmetals | C | An alloy is a mixture of a metal with one or more other elements. The other elements may be metals, nonmetals, or both. An alloy is formed by melting a metal and dissolving the other elements in it. The molten solution is then allowed to cool and harden. Alloys generally have more useful properties than pure metals. Se... |
Metal ions are surrounded by a sea of | (A) electrons (B) positive ions (C) negative ions (D) positive charges | A | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
An alloy of iron and carbon is | (A) more likely to rust than pure iron (B) weaker than pure iron (C) a mixture of two metals (D) known as steel | D | Metals are useful for many purposes because of their unique properties. However, pure metals may be less useful than mixtures of metals. For example, iron is not as strong as steel, which is a mixture of iron and small amounts of carbon. Steel is so strong that it can hold up huge bridges, like the one Figure 7.15. Ste... |
The alloy that contains iron, carbon, nickel, and chromium is called | (A) stainless steel (B) bronze (C) brass (D) gold | A | Metals are useful for many purposes because of their unique properties. However, pure metals may be less useful than mixtures of metals. For example, iron is not as strong as steel, which is a mixture of iron and small amounts of carbon. Steel is so strong that it can hold up huge bridges, like the one Figure 7.15. Ste... |
type of ion a metal forms | (A) alloy (B) metallic bond (C) metal (D) cation (E) iron (F) steel (G) metallic lattice | D | Ionic bonds form only between metals and nonmetals. Thats because metals want to give up electrons, and nonmetals want to gain electrons. Find sodium (Na) in the Figure 1.2. Sodium is an alkali metal in group 1. Like all group 1 elements, it has just one valence electron. If sodium loses that one electron, it will have... |
structure formed by metallic bonding | (A) alloy (B) metallic bond (C) metal (D) cation (E) iron (F) steel (G) metallic lattice | G | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
example of an alloy | (A) alloy (B) metallic bond (C) metal (D) cation (E) iron (F) steel (G) metallic lattice | F | An alloy is a mixture of a metal with one or more other elements. The other elements may be metals, nonmetals, or both. An alloy is formed by melting a metal and dissolving the other elements in it. The molten solution is then allowed to cool and harden. Alloys generally have more useful properties than pure metals. Se... |
any element that is a good conductor of electricity | (A) alloy (B) metallic bond (C) metal (D) cation (E) iron (F) steel (G) metallic lattice | C | Materials that have low resistance to electric current are called electric conductors. Many metalsincluding copper, aluminum, and steelare good conductors of electricity. The outer electrons of metal atoms are loosely bound and free to move, allowing electric current to flow. Water that has even a tiny amount of impuri... |
A metallic bond may form between a metal and any other element. | (A) true (B) false | B | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
example of a metal | (A) alloy (B) metallic bond (C) metal (D) cation (E) iron (F) steel (G) metallic lattice | E | We rely on metals, such as aluminum, copper, iron, and gold. Look around the room. How many objects have metal parts? Metals are used in the tiny parts inside your computer, in the wires of anything that uses electricity, and to make the structure of a large building, such as the one shown in the Figure 3.23. |
Metals can be shaped into thin sheets. | (A) true (B) false | A | The valence electrons surrounding metal ions are constantly moving. This makes metals good conductors of electricity. The lattice-like structure of metal ions is strong but quite flexible. This allows metals to bend without breaking. Metals are both ductile (can be shaped into wires) and malleable (can be shaped into t... |
mixture of a metal with one or more other elements | (A) alloy (B) metallic bond (C) metal (D) cation (E) iron (F) steel (G) metallic lattice | A | An alloy is a mixture of a metal with one or more other elements. The other elements may be metals, nonmetals, or both. An alloy is formed by melting a metal and dissolving the other elements in it. The molten solution is then allowed to cool and harden. Alloys generally have more useful properties than pure metals. Se... |
Metal ions are surrounded by a sea of positive charge. | (A) true (B) false | B | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
force of attraction between a metal ion and valence electrons it shares with other ions of the metal | (A) alloy (B) metallic bond (C) metal (D) cation (E) iron (F) steel (G) metallic lattice | B | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
Special bonds form in metals that do not form in other classes of elements. | (A) true (B) false | A | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
Bronze has been used for thousands of years. | (A) true (B) false | A | Most metal objects are made of alloys rather than pure metals. Objects made of four different alloys are shown in the Figure 1.1. Brass saxophone: Brass is an alloy of copper and zinc. It is softer than bronze and easier to shape. Its also very shiny. Notice the curved pieces in this shiny brass saxophone. Brass is use... |
Brass is an alloy of iron and copper. | (A) true (B) false | B | Most metal objects are made of alloys rather than pure metals. Objects made of four different alloys are shown in the Figure 1.1. Brass saxophone: Brass is an alloy of copper and zinc. It is softer than bronze and easier to shape. Its also very shiny. Notice the curved pieces in this shiny brass saxophone. Brass is use... |
A metallic lattice is more rigid than an ionic crystal. | (A) true (B) false | B | The valence electrons surrounding metal ions are constantly moving. This makes metals good conductors of electricity. The lattice-like structure of metal ions is strong but quite flexible. This allows metals to bend without breaking. Metals are both ductile (can be shaped into wires) and malleable (can be shaped into t... |
Metallic bonds explain some of the unique properties of metals. | (A) true (B) false | A | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
Metal ions form bonds with the valence electrons around them. | (A) true (B) false | A | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
Examples of metals include iron, zinc, and carbon. | (A) true (B) false | B | We rely on metals, such as aluminum, copper, iron, and gold. Look around the room. How many objects have metal parts? Metals are used in the tiny parts inside your computer, in the wires of anything that uses electricity, and to make the structure of a large building, such as the one shown in the Figure 3.23. |
A metallic lattice is held together by ionic bonds. | (A) true (B) false | B | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
Iron is stronger than steel. | (A) true (B) false | B | Metals are useful for many purposes because of their unique properties. However, pure metals may be less useful than mixtures of metals. For example, iron is not as strong as steel, which is a mixture of iron and small amounts of carbon. Steel is so strong that it can hold up huge bridges, like the one Figure 7.15. Ste... |
Most metal objects are made of alloys. | (A) true (B) false | A | Most metal objects are made of alloys rather than pure metals. Objects made of four different alloys are shown in the Figure 1.1. Brass saxophone: Brass is an alloy of copper and zinc. It is softer than bronze and easier to shape. Its also very shiny. Notice the curved pieces in this shiny brass saxophone. Brass is use... |
Bronze is a compound of copper and tin. | (A) true (B) false | B | Most metal objects are made of alloys rather than pure metals. Objects made of four different alloys are shown in the Figure 1.1. Brass saxophone: Brass is an alloy of copper and zinc. It is softer than bronze and easier to shape. Its also very shiny. Notice the curved pieces in this shiny brass saxophone. Brass is use... |
Gold jewelry is usually made of pure gold. | (A) true (B) false | B | Most metal objects are made of alloys rather than pure metals. Objects made of four different alloys are shown in the Figure 1.1. Brass saxophone: Brass is an alloy of copper and zinc. It is softer than bronze and easier to shape. Its also very shiny. Notice the curved pieces in this shiny brass saxophone. Brass is use... |
Which of the following changes is a chemical change? | (A) ice melting (B) wax melting (C) water boiling (D) wax burning | D | Most chemical changes are not as dramatic as exploding fireworks, so how can you tell whether a chemical change has occurred? There are usually clues. You just need to know what to look for. A chemical change has probably occurred if bubbles are released, there is a change of color, or an odor is produced. Other clues ... |
Most chemical reactions take place in labs. | (A) true (B) false | B | Chemistry can help you understand the world around you. Everything you touch, taste, or smell is made of chemicals, and chemical reactions underlie many common changes. For example, chemistry explains how food cooks, why laundry detergent cleans your clothes, and why antacid tablets relieve an upset stomach. Other exam... |
All changes in matter involve chemical reactions. | (A) true (B) false | B | Not all changes in matter involve chemical reactions. For example, there are no chemical reactions involved in changes of state. When liquid water freezes or evaporates, it is still water. No bonds are broken and no new products are formed. How can you tell whether a change in matter involves a chemical reaction? Often... |
Which statement is true of all chemical reactions? | (A) They can go in just one direction (B) They occur only in science labs (C) They break and reform bonds (D) They create new elements | C | All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. In some chemical reactions, called exothermic reactions, more energy is released when new bonds form in the products than is needed to break bonds in the reactants. The opposite is ... |
Evaporation is an example of a chemical change. | (A) true (B) false | B | Not all changes in matter involve chemical reactions. For example, there are no chemical reactions involved in changes of state. When liquid water freezes or evaporates, it is still water. No bonds are broken and no new products are formed. How can you tell whether a change in matter involves a chemical reaction? Often... |
Reactants and products in chemical reactions may be | (A) elements (B) compounds (C) exactly the same compounds (D) two of the above | D | A chemical reaction is a process in which some substances change into different substances. Substances that start a chemical reaction are called reactants. Substances that are produced in the reaction are called products. Reactants and products can be elements or compounds. A chemical reaction can be represented by thi... |
All chemical changes in matter involve | (A) changes of state (B) chemical reactions (C) changes in color (D) two of the above | B | Not all changes in matter involve chemical reactions. For example, there are no chemical reactions involved in changes of state. When liquid water freezes or evaporates, it is still water. No bonds are broken and no new products are formed. How can you tell whether a change in matter involves a chemical reaction? Often... |
Reactants and products can be elements or compounds. | (A) true (B) false | A | A chemical reaction is a process in which some substances change into different substances. Substances that start a chemical reaction are called reactants. Substances that are produced in the reaction are called products. Reactants and products can be elements or compounds. A chemical reaction can be represented by thi... |
Chemical reactions may occur quickly or slowly. | (A) true (B) false | A | A chemical reaction is a process in which some substances change into different substances. Substances that start a chemical reaction are called reactants. Substances that are produced in the reaction are called products. Reactants and products can be elements or compounds. Chemical reactions are represented by chemica... |
Which statement is true about a precipitate? | (A) It is a solid (B) It settles out of a liquid solution (C) It is evidence of a chemical reaction (D) all of the above | D | When water evaporates, it leaves behind a solid precipitate of minerals, as shown in Figure 1.2. When the water in glass A evaporates, the dissolved mineral particles are left behind. Water can only hold a certain amount of dissolved minerals and salts. When the amount is too great to stay dissolved in the water, the p... |
Some chemical reactions can proceed in just one direction. | (A) true (B) false | A | The arrow in Figure 8.2 shows that the reaction goes from left to right, from hydrogen and oxygen to water. The reaction can also go in the reverse direction. If an electric current passes through water, water molecules break down into molecules of hydrogen and oxygen. This reaction would be represented by a right-to-l... |
An example of a chemical change is water boiling. | (A) true (B) false | B | A chemical change occurs whenever matter changes into an entirely different substance with different chemical properties. A chemical change is also called a chemical reaction. Many complex chemical changes occur to produce the explosions of fireworks. An example of a simpler chemical change is the burning of methane. M... |
Freezing involves a chemical reaction. | (A) true (B) false | B | Not all changes in matter involve chemical reactions. For example, there are no chemical reactions involved in changes of state. When liquid water freezes or evaporates, it is still water. No bonds are broken and no new products are formed. How can you tell whether a change in matter involves a chemical reaction? Often... |
A banana turning brown is a chemical change. | (A) true (B) false | A | A change in color is just one of several potential signs that a chemical reaction has occurred. Other potential signs include: Change in temperature-Heat is released or absorbed during the reaction. Production of a gas-Gas bubbles are released during the reaction. Production of a solid-A solid settles out of a liquid s... |
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