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