CHEM QUICK REVISION

Pauli Exclusion Principle

(1) no more than two electrons can occupy the same orbital and (2) two electrons in the same orbital must have opposite spins

if an ionic compound is between 1 metal and 1 non-metal, the name ends with

ide

if an ionic compound if between a metal and a polyatomic ion, it ends with…

ate or ite

for covalent/molecular compounds, the write the name you

use the prefixes

periodic trend for electronegativity

increases up a group and across a period

periodic trend for ionisation energy

increases up a group and across a period

periodic trend for atomic radius

increases down a group decreases across a period

periodic trend for nuclear charge

stays constant in a group and increases across a period

periodic trend for shielding

increases down a group and is constant in a period

what is heat of reaction or enthalpy change

the amount of energy lost or gained during the reaction

the properties of most metals are…

good conducturs of electricity, good conductors of heat, high densities, malleable, ductile, low ionisation energies and low electronegativities

why are metals malleable and ductile

Because the delocalised electrons are able to move and prevent repulsion between the cations

the properties of most non-metals are….

brittle, bad conductors of heat and electricity, not tough. can be solid liquid or gas at room temperature

what is the ideal gas equation

PV = nRT where ..

p = pressure (in kPa)

v = volume (in L)

n = moles (in mol)

R = gas constant (8.31Jk/mol)

T = temperature (in kelvin)

the molar volume of any gas at STP is

22.7 Lmol

what affects the rate of a reaction

surface area, concentration, gas pressire, temperature and catalysts.

whats an isotope?

Atoms with the same number of protons but different numbers of neutrons

Arrangement of 2 domains

Furthest apart they can be is 180 degrees and electron geometry is linear

arrangement of 3 domains

furthest apart they can be is 120 degrees. Electron geometry is trigonal planar. If all domains are bonding, mol geometry is trigonal planar but if one lone pair, mol geometry is bent

arrangement of 4 domains

furthest apart is 109 degrees. Electron geometry is tetrahedral. if all domain bonding then mol geometry is tetrahedral. if one lone pair, mol geometry is trigonal pyramidal and if 2 lone pairs mol geometry is bent

Aufbau Principle

in the ground state of an atom or ion, electrons fill subshells of the lowest available energy, then they fill subshells of higher energy.

Hund's Rule

orbitals will be singly occupied before being doubly occupied