Chem Topic 4 Vocab

Electronegativity

Electronegativity

A relative measure of the attraction that an atom has for a shared pair of electrons when it is covalently bonded to another atom

Electropositive

lower EN, has a more positive charge in the relationship

Electrostatic

attractive or repuslive foreces between particles

Isoelectronic

2 atoms/ions/molecules that have the same electron structure and number of valence electrons

Lattice Enthalpy

Enthalpy change when 1 mol of a crystal lattice is turned into it’s infinitely seperated gaseous ions under standard conditions

Volatile

the tendency of a substance to vaporize

Electron Domain

number of pairs of electrons on a central atom

Allotropes

compounds of the same element that differ in structure

Ionic bond

an electrostatic force between positive and negative ions

Covalent bond

involves the electrostatic attraction between nuclei of two atoms and the electrons of their outer shells

Polar covalent bond

a covalent bond in which the atoms have an unequal attraction for electrons, and so the sharing is unequal

Dative covalent bond

a covalent bond in which both electrons come from the same atom

Valence Shell Electron Pair Repulsion Theory

the best arrangement of a given number of electron domains is the one that minimizes the repulsion among them

2 bonding pairs

linear 180

3 bonding pairs

trigonal planar 120

2 bonding pairs 1 lone pair

modified trigonal planar 118

4 bonding pairs

tetrahedral 109.5

3 bonding pairs 1 lone pair

trigonal pyramidal 107

2 bonding pairs 2 lone pairs

v-shaped 105

Metallic Bond

Positive metal ions are surrounded by a ‘sea’ of mobile negative electrons

Malleable

the ability of a substance to be hammered or beaten into thin sheets.

Ductile

the ability of a substance to be drawn or pulled through a small opening to produce a wire.

Relative atomic mass

The weighted average of the masses of the isotopes relative to 1/12 of the mass of a carbon-‐12 atom