5 – 3 Electron Configuration and Periodic Properties

Atomic Radius

• As you move down a group it increases

• The outermost e- are being added to higher energy levels (further from the nucleus.

Atomic Radius

• As you move across a period, it decreases

• Even though e- are being added, they are added to the same energy level (same distance from the nucleus).

Atomic Radius

• The charge on the nucleus increases as you move across the period and so it has a “tighter” hold on the e- being added.

Shielding Effect

• The reduction of the attractive force between a nucleus and its outer electrons due to the blocking effect of inner electrons.

Ionization Energy

• The amount of energy needed to remove an electron from an atom

Ion

• An atom that has gained or lost an e-

• If it has gained an e-, it will be _____.

• If it has lost an e-, it will be _____.

Ionization Energy

• As you go down a group, it decreases

• Shielding effect and electrons are being added to higher energy levels.

Ionization Energy

• As you move across a period, it increases

• The charge on the nucleus increases as you move across the period and so it has a “tighter” hold on the e- being added.

Electron Affinity

• The attraction of an atom for an additional e-

• Metals tend to have low EA

• Non-metals tend to have high EA

EA

• As you move down a group, EA decreases.

• Shielding Effect and electrons are being added to higher energy levels.

EA

• It increases as you move across the periodic table.

• The charge on the nucleus increases as you move across the period and so it has a “tighter” hold on the e- being added.

Electronegativity

• Tendency for an atom to attract e- to itself when combined with another atom.

• F is the most EN

• EN decreases as you move down a group

• EN increases as you move across a period

Electronegativity

• Based on the Pauling Scale.

• Linus Pauling• 28 Feb 1901 –

19 Aug 1994