sub-shells and atomic orbitals

sub-shells

regions of the principal quantum shells where electrons exist in defined areas associated with particular amounts of energy…s, p, d

atomic orbitals

regions of space outside the nucleus that can be occupied by a maximum of two electrons…s, p, d, f…have different shapes

s orbitals

one orbital

p orbitals

three orbitals

d orbitals

five orbitals

filling the shells

1s, 1p, 2s, 2p, 3s, 3p, 4s, 3d, 4p

spin-pair repulsion

pair of electrons in the same orbital repel each other because they have the same charge…pairing the spinning electrons so they spin in opposite directions reduces repulsion…repulsion is more than that of single electron in separate orbitals…hence shells are filled one at a time before pairing

free radical

a species with one or more than one unpaired electron

species

different particles like atoms or ions

atomic radius

increases going down any group and decreases across a period…the greater attractive force of the increased nuclear charge on the outer shell electrons pulls them together

ionic radius

increases down any group and decreases across periods…the increasing nuclear charge attracts the electrons in the valence shell closer to the nucleus with increasing atomic number, shielding is the same and has less effect…cations are smaller than original atoms and anions are larger than original atoms