Unit 2: Molecular and Ionic Compound Structure and Properties

Flashcards about Molecular and Ionic Compound Structure and Properties.

Nonpolar Covalent Bond

Valence electrons shared between atoms of similar electronegativity.

Polar Covalent Bond

Valence electrons shared between atoms of unequal electronegativity. The atom with a higher electronegativity will develop a slightly negative charge relative to the other atom in the bond.

Chemical Bond

Attraction between the nucleus of one atom and the electrons of another.

Ionic Bond

Transferring electrons (usually involving a metal and a nonmetal).

Covalent Bond

Sharing electrons (usually involves nonmetals).

Metallic Bond

Electrons not associated with a single atom or molecule; involves delocalized bonding.

Delocalized Bonding

Electrons are not associated with any individual atom but are associated with all the atoms involved in a metallic bond.

Bond Polarity

Differences in electronegativity values of 2 elements.

Ionic Solids

Held together by electrostatic attractions.

Bond Energy

Energy it takes to break the bond. You get energy when you make a bond.

Lattice Energy

Related to the cation charge, anion charge, cation period, and anion period.

Alloy

Combining 2+ metallic elements.

Substitutional Alloy

Atoms of comparable radii (size); one atom substitutes for another atom in the lattice.

Interstitial Alloy

Atoms of different radii (especially nonmetals); a smaller atom fills the space between larger atoms.

Lewis Diagrams

Models that represent chemical substances, show the connectivity between atoms, display the bond order, and show valence electrons that are not used for bonding.

Octet Rule

Except for hydrogen & boron, when bonding, all atoms end up with 8 electrons around them. Group 13 is cool with 6 electrons.

Formal Charge

Valence e- - Non-binding Valence e- - Bonding e-/2.

Resonance Structure

When a molecule or polyatomic ion has multiple contributors to its structures, write them all, connected by double-ended arrows.

VSEPR (Valence Shell Electron Pair Repulsion)

Bonds and lone pairs of electrons (electron domains) are negative in nature, therefore bonds and lone pairs will arrange themselves in order to minimize repulsion.

Steric Number

Number of electron domains (bonds and lone pairs) Each electron domain is counted equally - Single/double/triple bonds are considered equivalent.

Hybrid Orbitals

Orbitals formed by 2+ atomic orbitals, specifically 's' and 'p'.

Electron Domain

Region containing electron pairs. Each pair of nonbonding electrons & bonds that connect atoms = 1 domain. Double & triple bonds only count as one domain.

Sigma (σ) Bonds

Characterized by head-to-head overlap. Cylindrical symmetry of electron density about the internuclear axis.

Pi (π) Bonds

Characterized by side-to-side overlap. Electron density above and below the internuclear axis. In multiple bonds, one of the bonds is σ and the rest are π bonds.