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tetrahedral : shape in which four outside groups are placed around a central atom such that a three-dimensional shape is generated with four corners and 109.5° angles between each pair and the central atom | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-key-terms |
trigonal bipyramidal : shape in which five outside groups are placed around a central atom such that three form a flat triangle with 120° angles between each pair and the central atom, and the other two form the apex of two pyramids, one above and one below the triangular plane | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-key-terms |
trigonal planar : shape in which three outside groups are placed in a flat triangle around a central atom with 120° angles between each pair and the central atom | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-key-terms |
triple bond : bond in which three pairs of electrons are shared between two atoms | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-key-terms |
valence shell electron-pair repulsion theory (VSEPR) : theory used to predict the bond angles in a molecule based on positioning regions of high electron density as far apart as possible to minimize electrostatic repulsion | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-key-terms |
vector : quantity having magnitude and direction | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-key-terms |
Atoms gain or lose electrons to form ions with particularly stable electron configurations. The charges of cations formed by the representative metals may be determined readily because, with few exceptions, the electronic structures of these ions have either a noble gas configuration or a completely filled electron she... | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-summary |
Covalent bonds form when electrons are shared between atoms and are attracted by the nuclei of both atoms. In pure covalent bonds, the electrons are shared equally. In polar covalent bonds, the electrons are shared unequally, as one atom exerts a stronger force of attraction on the electrons than the other. The ability... | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-summary |
Chemists use nomenclature rules to clearly name compounds. Ionic and molecular compounds are named using somewhat-different methods. Binary ionic compounds typically consist of a metal and a nonmetal. The name of the metal is written first, followed by the name of the nonmetal with its ending changed to âide. For exa... | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-summary |
Valence electronic structures can be visualized by drawing Lewis symbols (for atoms and monatomic ions) and Lewis structures (for molecules and polyatomic ions). Lone pairs, unpaired electrons, and single, double, or triple bonds are used to indicate where the valence electrons are located around each atom in a Lewis s... | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-summary |
In a Lewis structure, formal charges can be assigned to each atom by treating each bond as if one-half of the electrons are assigned to each atom. These hypothetical formal charges are a guide to determining the most appropriate Lewis structure. A structure in which the formal charges are as close to zero as possible i... | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-summary |
VSEPR theory predicts the three-dimensional arrangement of atoms in a molecule. It states that valence electrons will assume an electron-pair geometry that minimizes repulsions between areas of high electron density (bonds and/or lone pairs). Molecular structure, which refers only to the placement of atoms in a molecul... | https://openstax.org/books/chemistry-atoms-first-2e/pages/4-summary |
bond order = ( number of bonding electron ) â ( number of antibonding electrons ) 2 bond order = ( number of bonding electron ) â ( number of antibonding electrons ) 2 | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-equations |
antibonding orbital : molecular orbital located outside of the region between two nuclei; electrons in an antibonding orbital destabilize the molecule | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
bond order : number of pairs of electrons between two atoms; it can be found by the number of bonds in a Lewis structure or by the difference between the number of bonding and antibonding electrons divided by two | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
bonding orbital : molecular orbital located between two nuclei; electrons in a bonding orbital stabilize a molecule | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
degenerate orbitals : orbitals that have the same energy | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
diamagnetism : phenomenon in which a material is not magnetic itself but is repelled by a magnetic field; it occurs when there are only paired electrons present | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
homonuclear diatomic molecule : molecule consisting of two identical atoms | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
hybrid orbital : orbital created by combining atomic orbitals on a central atom | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
hybridization : model that describes the changes in the atomic orbitals of an atom when it forms a covalent compound | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
linear combination of atomic orbitals : technique for combining atomic orbitals to create molecular orbitals | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
molecular orbital : region of space in which an electron has a high probability of being found in a molecule | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
molecular orbital diagram : visual representation of the relative energy levels of molecular orbitals | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
molecular orbital theory : model that describes the behavior of electrons delocalized throughout a molecule in terms of the combination of atomic wave functions | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
node : plane separating different lobes of orbitals, where the probability of finding an electron is zero | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
overlap : coexistence of orbitals from two different atoms sharing the same region of space, leading to the formation of a covalent bond | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
paramagnetism : phenomenon in which a material is not magnetic itself but is attracted to a magnetic field; it occurs when there are unpaired electrons present | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
pi bond (Ï bond) : covalent bond formed by side-by-side overlap of atomic orbitals; the electron density is found on opposite sides of the internuclear axis | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
s-p mixing : change that causes Ïporbitals to be less stable than Ïporbitals due to the mixing ofsandp-based molecular orbitals of similar energies. | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
sigma bond (Ï bond) : covalent bond formed by overlap of atomic orbitals along the internuclear axis | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
sphybrid orbital : one of a set of two orbitals with a linear arrangement that results from combining onesand oneporbital | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
sp2hybrid orbital : one of a set of three orbitals with a trigonal planar arrangement that results from combining onesand twoporbitals | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
sp3hybrid orbital : one of a set of four orbitals with a tetrahedral arrangement that results from combining onesand threeporbitals | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
sp3dhybrid orbital : one of a set of five orbitals with a trigonal bipyramidal arrangement that results from combining ones, threep, and onedorbital | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
sp3d2hybrid orbital : one of a set of six orbitals with an octahedral arrangement that results from combining ones, threep, and twodorbitals | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
valence bond theory : description of bonding that involves atomic orbitals overlapping to form Ï or Ï bonds, within which pairs of electrons are shared | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
Ï bonding orbital : molecular orbital formed by side-by-side overlap of atomic orbitals, in which the electron density is found on opposite sides of the internuclear axis | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
Ï* bonding orbital : antibonding molecular orbital formed by out of phase side-by-side overlap of atomic orbitals, in which the electron density is found on both sides of the internuclear axis, and there is a node between the nuclei | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
Ï bonding orbital : molecular orbital in which the electron density is found along the axis of the bond | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
Ï* bonding orbital : antibonding molecular orbital formed by out-of-phase overlap of atomic orbital along the axis of the bond, generating a node between the nuclei | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-key-terms |
Valence bond theory describes bonding as a consequence of the overlap of two separate atomic orbitals on different atoms that creates a region with one pair of electrons shared between the two atoms. When the orbitals overlap along an axis containing the nuclei, they form a Ï bond. When they overlap in a fashion that ... | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-summary |
We can use hybrid orbitals, which are mathematical combinations of some or all of the valence atomic orbitals, to describe the electron density around covalently bonded atoms. These hybrid orbitals either form sigma (Ï) bonds directed toward other atoms of the molecule or contain lone pairs of electrons. We can determ... | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-summary |
Multiple bonds consist of a Ï bond located along the axis between two atoms and one or two Ï bonds. The Ï bonds are usually formed by the overlap of hybridized atomic orbitals, while the Ï bonds are formed by the side-by-side overlap of unhybridized orbitals. Resonance occurs when there are multiple unhybridized or... | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-summary |
Molecular orbital (MO) theory describes the behavior of electrons in a molecule in terms of combinations of the atomic wave functions. The resulting molecular orbitals may extend over all the atoms in the molecule. Bonding molecular orbitals are formed by in-phase combinations of atomic wave functions, and electrons in... | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-summary |
We can describe the electronic structure of diatomic molecules by applying molecular orbital theory to the valence electrons of the atoms. Electrons fill molecular orbitals following the same rules that apply to filling atomic orbitals; Hundâs rule and the Aufbau principle tell us that lower-energy orbitals will fill... | https://openstax.org/books/chemistry-atoms-first-2e/pages/5-summary |
% X = mass X mass compound à 100 % % X = mass X mass compound à 100 % | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-equations |
molecular or molar mass ( amu or g mol ) empirical formula mass ( amu or g mol ) = n formula units/molecule molecular or molar mass ( amu or g mol ) empirical formula mass ( amu or g mol ) = n formula units/molecule | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-equations |
(A x B y ) n = A nx B ny | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-equations |
M = mol solute L solution M = mol solute L solution | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-equations |
C 1 V 1 = C 2 V 2 | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-equations |
Percent by mass = mass of solute mass of solution à 100 Percent by mass = mass of solute mass of solution à 100 | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-equations |
ppm = mass solute mass solution à 10 6 ppm ppm = mass solute mass solution à 10 6 ppm | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-equations |
ppb = mass solute mass solution à 10 9 ppb ppb = mass solute mass solution à 10 9 ppb | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-equations |
aqueous solution : solution for which water is the solvent | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
Avogadroâs number (NA) : experimentally determined value of the number of entities comprising 1 mole of substance, equal to 6.022ÃÃ1023molâ1 | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
concentrated : qualitative term for a solution containing solute at a relatively high concentration | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
concentration : quantitative measure of the relative amounts of solute and solvent present in a solution | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
dilute : qualitative term for a solution containing solute at a relatively low concentration | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
dilution : process of adding solvent to a solution in order to lower the concentration of solutes | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
dissolved : describes the process by which solute components are dispersed in a solvent | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
empirical formula mass : sum of average atomic masses for all atoms represented in an empirical formula | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
formula mass : sum of the average masses for all atoms represented in a chemical formula; for covalent compounds, this is also the molecular mass | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
mass percentage : ratio of solute-to-solution mass expressed as a percentage | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
mass-volume percent : ratio of solute mass to solution volume, expressed as a percentage | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
molar mass : mass in grams of 1 mole of a substance | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
molarity (M) : unit of concentration, defined as the number of moles of solute dissolved in 1 liter of solution | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
mole : amount of substance containing the same number of atoms, molecules, ions, or other entities as the number of atoms in exactly 12 grams of12C | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
parts per billion (ppb) : ratio of solute-to-solution mass multiplied by 109 | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
parts per million (ppm) : ratio of solute-to-solution mass multiplied by 106 | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
percent composition : percentage by mass of the various elements in a compound | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
solute : solution component present in a concentration less than that of the solvent | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
solvent : solution component present in a concentration that is higher relative to other components | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
volume percentage : ratio of solute-to-solution volume expressed as a percentage | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-key-terms |
The formula mass of a substance is the sum of the average atomic masses of each atom represented in the chemical formula and is expressed in atomic mass units. The formula mass of a covalent compound is also called the molecular mass. Due to the use of the same reference substance in defining the atomic mass unit and t... | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-summary |
The chemical identity of a substance is defined by the types and relative numbers of atoms composing its fundamental entities (molecules in the case of covalent compounds, ions in the case of ionic compounds). A compoundâs percent composition provides the mass percentage of each element in the compound, and it is oft... | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-summary |
Solutions are homogeneous mixtures. Many solutions contain one component, called the solvent, in which other components, called solutes, are dissolved. An aqueous solution is one for which the solvent is water. The concentration of a solution is a measure of the relative amount of solute in a given amount of solution. ... | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-summary |
In addition to molarity, a number of other solution concentration units are used in various applications. Percentage concentrations based on the solution componentsâ masses, volumes, or both are useful for expressing relatively high concentrations, whereas lower concentrations are conveniently expressed using ppm or ... | https://openstax.org/books/chemistry-atoms-first-2e/pages/6-summary |
percent yield = ( actual yield theoretical yield ) Ã 100 percent yield = ( actual yield theoretical yield ) Ã 100 | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-equations |
acid : substance that produces H3O+when dissolved in water | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
acid-base reaction : reaction involving the transfer of a hydrogen ion between reactant species | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
actual yield : amount of product formed in a reaction | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
analyte : chemical species of interest | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
balanced equation : chemical equation with equal numbers of atoms for each element in the reactant and product | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
base : substance that produces OHâwhen dissolved in water | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
buret : device used for the precise delivery of variable liquid volumes, such as in a titration analysis | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
chemical equation : symbolic representation of a chemical reaction | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
coefficient : number placed in front of symbols or formulas in a chemical equation to indicate their relative amount | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
combustion analysis : gravimetric technique used to determine the elemental composition of a compound via the collection and weighing of its gaseous combustion products | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
combustion reaction : vigorous redox reaction producing significant amounts of energy in the form of heat and, sometimes, light | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
complete ionic equation : chemical equation in which all dissolved ionic reactants and products, including spectator ions, are explicitly represented by formulas for their dissociated ions | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
end point : measured volume of titrant solution that yields the change in sample solution appearance or other property expected for stoichiometric equivalence (seeequivalence point) | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
equivalence point : volume of titrant solution required to react completely with the analyte in a titration analysis; provides a stoichiometric amount of titrant for the sampleâs analyte according to the titration reaction | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
excess reactant : reactant present in an amount greater than required by the reaction stoichiometry | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
gravimetric analysis : quantitative chemical analysis method involving the separation of an analyte from a sample by a physical or chemical process and subsequent mass measurements of the analyte, reaction product, and/or sample | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
half-reaction : an equation that shows whether each reactant loses or gains electrons in a reaction. | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
indicator : substance added to the sample in a titration analysis to permit visual detection of the end point | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
insoluble : of relatively low solubility; dissolving only to a slight extent | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
limiting reactant : reactant present in an amount lower than required by the reaction stoichiometry, thus limiting the amount of product generated | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
molecular equation : chemical equation in which all reactants and products are represented as neutral substances | https://openstax.org/books/chemistry-atoms-first-2e/pages/7-key-terms |
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