Chemistry Chapter 8: Covalent Bond
Tetrahedral angle
A bond angle of 109.5 that results when a central atom forms four bonds directed toward the center of a regular tetrahedron.
Sigma bond
A bond formed when two atomic orbitals combine to form a molecular orbital that is symmetrical around the axis connecting the two atomic nuclei.
Single covalent bond
A bond formed when two atoms share a pair of electrons.
Double covalent bond
A bond in which two atoms share two pairs of electrons.
Molecular formula
A chemical formula of a compound that shows the kinds and numbers of atoms present in a molecule of a compound.
Structural formula
A chemical formula that shows the arrangement of atoms in a molecule or a poly-atomic ion; each dash between a pair of atoms indicates a pair of shared electrons.
Molecular compound
A compound that is composed of molecules.
Polar covalent bond (polar bond)
A covalent bond between atoms in which the electrons are shared unequally.
Coordinate covalent bond
A covalent bond in which one atom contributes both bonding elements.
Pi bond
A covalent bond in which the bonding electrons are most likely to be found in sausage-shaped regions above and below the bond axis of the bonded atoms.
Nonpolar covalent bond
A covalent bond in which the electrons are shared equally by the two atoms.
Triple covalent bond
A covalent bond in which three pairs of electrons are shared by two atoms.
Bonding orbital
A molecular orbital that can be occupied by two electrons of a covalent bond.
Polar molecule
A molecule in which one side of the molecule is slightly negative and the opposite side is slightly positive.
Diatomic molecule
A molecule that contains two atoms.
Dipole
A molecule that has two poles, or regions, with opposite charges.
Molecule
A neutral group of atoms joined together by covalent bonds
Unshared pair
A pair of valence electrons that is not shared between atoms.
Polyatomic ion
A tightly bound group of atoms that behaves as a unit and has a positive or negative change.
Molecular orbital
An orbital that applies to the enitre molecule. When two atoms combine, this model assumes that their atomic orbitals overlap to produce molecular orbitals, or orbitals that apply to the entire molecule.
Covalent Bond
Atoms held together by sharing electrons. A bond formed by the sharing of electrons between atoms.
Hydrogen bonds
Attractive forces in which a hydrogen atom covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom.
Resonance structure
One of the two or more equally valid electron dot structures of a molecule or polyatomic ion. These structures occur when it is possible to draw two or more valid electron pairs for a molecule or ion.
Bond dissociation energy
The energy that is required to break the bond between two covalently bonded atoms; this value is usually expressed in kJ per mol of substance.
VSEPR theory
Valence-shell electron-pair repulsion theory; because electron pairs repel, molecules adjust their shapes so that valence electron pairs are as far apart as possible.
