Electron config for Chromium (start with [Ne])
[Ne] 3s2 3p6 4s1 3d5

Electron config for copper (start with [Ar])
[Ar] 4s1 3d10

Things that affect periodic trends
electron repulsion
proton count
shielding

In what direction does atomic radius/ionic radius increase (because less protons pulling the shell in)
bottom left

In what direction does electronegativity/electron affinity increase (because effective nuclear charge higher and atomic radius lower)
top right

What is ionization energy the opposite of 
electronegativity

Why is it easier for oxygen to lose an electron than nitrogen (hint: 2 electrons are in the same orbital in oxygen, whereas in nitrogen all orbitals are half full)
electron electron repulsion