General Chemistry: Atoms First (2nd Edition) - Chapter 4 - Key Words

Covalent bond

This noun phrase describes a bond that results from the sharing of electrons between atoms.

Molecule

This noun describes a unit of matter held together by covalent bonds.

Lattice energy (U)

This noun phrase describes the amount of energy that must be supplied to break an ionic solid into its individual gaseous ions and is thus a measure of strength of a solid's ionic bonds.

Bond length

This noun phrase describes the distance at which two covalently bonded particles are kept from each other. This occurs when the net attractive forces (electron-electron, proton-proton, electron-proton) are greatest.

Structural formula

This noun phrase describes the method of displaying the molecular make-up of a substance by denoting each atom of a molecule with its chemical symbol and connecting covalently bonded atoms with lines.

Chemical formula

This noun phrase describes the denoting of a compound by listing the symbols of its constituent components and using subscripts to denote the number of atoms of each element.

Bond dissociation energy (D)

This noun phrase describes the amount of energy that must be supplied to break a covalent bond between two atoms in an isolated molecule in the gaseous state. These values are always positive due to the requirement of energy being added to the system.

Polar covalent bond

This noun phrase describes a bond where electrons are shared unequally between two atoms without being completely transferred.

Partial charge (𝛿)

This noun phrase describes which atom is electron-rich and which atom is electron-poor in a polar covalent bond. The electron-rich atom is denoted 𝛿⁻, while the electron-poor atom is denoted 𝛿⁺.

Electronegativity (EN)

This noun phrase is the term for the following definition: the ability of an atom in a molecule to attract shared electrons in a covalent bond.

Electron-dot structure (Lewis structure)

This noun phrase describes the representation of an atom's valence electrons with dots and indicates, by placement of those dots, how the valence electrons are distributed within a molecule.

Lone pair

This noun phrase describes a pair of electrons, in a covalently bonded atom, that is not participating in bonding.

Bonding pair

This noun phrase describes a pair of electrons in an atom that are participating in a molecular bond.

Single bond

This noun phrase describes one pair of electrons being shared between two atoms in a molecule.

Double bond

This noun phrase describes two pairs of electrons being shared between two atoms in a molecule. Carbon, nitrogen, and oxygen tend to be capable of forming these bonds.

Triple bond

This noun phrase describes three pairs of electrons being shared between two atoms in a molecule. Carbon and nitrogen tend to be capable of forming these bonds.

Bond order

This noun phrase numerically describes the number of electron pairs shared between two atoms.

Coordinate covalent bond

This noun phrase describes the type of bond whereby a single atom brings both electrons to be shared.

Resonance hybrid

This noun phrase describes two or more valid electron-dot structures for a molecule that leads to a molecular structure that is the average of the different bonding possibilities.

Formal charge

This noun phrase describes the change in charge of an atom compared with that atom participating in a molecular bond. It is calculated by:

(Number of valence electrons in free atom) - ½(Number of bonding electrons) - (Number of non-bonding electrons)

Radical

This noun describes substances with an odd number of electrons, meaning that there is one free, unpaired electron.

Dimerize

This noun describes the act of a substance bonding to an idential copy of itself to become stable. This commonly occurs with substances that are radicals.