Bonding and Molecular Structure

This set of vocabulary flashcards covers the fundamental principles of chemical bonding, ionic and covalent compounds, nomenclature, Lewis structures, molecular geometry, and bond polarity.

Bonding

The joining of two atoms in a stable arrangement.

Ionic bonds

Bonds that result from the transfer of electrons from one element to another, typically forming between a metal and a nonmetal.

Covalent bonds

Bonds that result from the sharing of electrons between two atoms, typically formed when two nonmetals combine or when a metalloid bonds to a nonmetal.

Molecule

A compound or element containing two or more atoms joined together with covalent bonds.

Ions

Charged species in which the number of protons and electrons in an atom is unequal.

Cations

Positively charged ions that have fewer electrons than protons; they are typically formed by metals losing electrons.

Anions

Negatively charged ions that have more electrons than protons; they are typically formed by nonmetals gaining electrons.

Ionic charge of Groups 1A, 2A, and 3A

For these main group metals, the group number is equal to the charge on the cation.

Ionic charge of Groups 6A and 7A

For these main group nonmetals, the anion charge is equal to $8 - ( ext{the group number})$.

Suffix "-ide"

The ending used to name anions by replacing the original ending of the element name, such as chlorine becoming chloride.

Naming Method [1] for variable charge metals

A system where the name of the cation is followed by a Roman numeral in parentheses to indicate its charge, such as iron(II).

Suffixes "-ous" and "-ic"

Suffixes used in Method [2] for naming variable charge metals; "-ous" is for the cation with a smaller charge and "-ic" is for the cation with a higher charge.

Polyatomic ion

A cation or anion that contains more than one atom, such as carbonate ($CO_3^{2-}$) or sulfate ($SO_4^{2-}$).

Lone pairs

Unshared electron pairs, also known as nonbonded electron pairs.

Octet rule

The principle that main group elements (except hydrogen) are especially stable when they possess eight electrons in their outer shell.

Lewis structures

Electron-dot structures for molecules that show the connectivity between atoms and the location of all valence electrons.

Double bond

A multiple bond containing four electrons shared in two two-electron bonds.

Triple bond

A multiple bond containing six electrons shared in three two-electron bonds.

VSEPR theory

Valence Shell Electron Pair Repulsion theory, which determines molecular shape based on the arrangement that keeps electron groups as far away from each other as possible.

Linear

A molecular shape where an atom is surrounded by only two groups, resulting in a bond angle of $180^{\circ}$.

Trigonal planar

A molecular shape where an atom is surrounded by three groups, resulting in bond angles of $120^{\circ}$.

Tetrahedral

A molecular shape where an atom is surrounded by four groups, resulting in bond angles of $109.5^{\circ}$.

Trigonal pyramid

A molecular shape where an atom is surrounded by four groups, including one lone pair, with bond angles of approximately $107^{\circ}$.

Bent

A molecular shape where an atom is surrounded by four groups, including two lone pairs, with a bond angle of approximately $105^{\circ}$.

Electronegativity

A measure of an atom's attraction for electrons in a bond.

Nonpolar bond

A bond where the electrons are shared equally because the electronegativities of the two atoms are equal or similar (difference less than $0.5$ units).

Polar covalent bond

Also called a dipole; a bond where electrons are shared unequally due to an electronegativity difference between $0.5$ and $2.0$ units.