Ml

Describes orbitals withing a subshell.

How to Determine specific value of Ml?

1. Determine how many orbitals you have within that subshell.

• Total # orbitals = 2l + 1
  • s-block = 1
  • p-block = 3
  • d-block = 5
  • f-block = 7

1. Draw lines representing each orbital
2. Label each orbital with value of ml, starting with most negative (-1,0,1)
3. Use electron configuration to determine how many electrons within each subshell.

O2

1s2 2s2 2p4 = 4 2p electrons

Hund's Rule

Each orbital is filled with 1 electron first, fill starting from the left.

• Single occupied orbitals all have the same spin, starting with up-spin first.

• The last electron placed gives you ml value, for oxygen, ml = -1

Paired Electrons

2 electrons in each orbital

Unpaired Electrons

Only 1 electron in each orbital.

Number of electrons for ml calculations are just for subshell, not the number of valence electrons (not all s & p).

Core electrons are everything in the electron configuration minus the number of valence electrons.

Octet Rule

8 electrons are the most stable for most types of atoms.

s & p blocks are most stable when they have a full octet of valence electrons.

Metals tend to lose electrons b/c they have fewer valence electrons.

Ionization Energy

• First ionization energy

• The energy required remove electrons from their gaseous state.

• Increases as we move up and to the right.

• Noble gasses are most stable.

  • Harder to remove from octet
  • Harder to remove from energy levels close to the nucleus.

First Ionization Energy

M(g) -> M^+(g) + e^-

(g) represent a gaseous state for magnesium/atoms

Second Ionization Energy

M^+(g) -> M^2+(g) + e^-

• Easier to remove electron from partially filled valence shell.
• Noble gases have a lower second ionization energy then their first b/c they are less stable.

Octet Rule

Predicting Valency Bonding Capacity

An atom will generally form 1 bond per electron it is missing/over 8.

O2 has 6 valence electrons so the valency of oxygen is 2. 2 short of 8. Wants to form 2 single covalent bonds.

Valency is always positive!

Exceptions

d and f-block elements

Electron deficient: H and He are stable with 2.

Expanded octet: May have more than 8 valence and be stable.

Radicals

Compounds with an odd number of electrons

Spectroscopy

• Higher energy means bond is stronger.
• Triple bonds > double bonds > single bonds.