Periodic Trends

this cover slides 18-28 :)

Atomic Radius

Measures the size of an atom from the nucleus' center to the valence electron

Atomic radius decreases

Across a period

Atomic radius increases

Down a group

Ionic Radius

Measures the size of atoms after they gain/lose electrons

Positive Ions

-Losing ions
-Radius decreases

Negative Ions

-Gaining electrons
-Radius increases
-Repulsion between extra electrons increases

Electronegativity

An atoms attraction for electrons

Electronegativity decreases

Down a group
-more likely to lose electrons
-electrons are loosely held

Electronegativity Increases

Across a period
-Atoms are held tightly
-think of the noble gasses where it's difficult to remove their electrons

Ionization Energy

Amount of energy required to remove a valence electron from an atom

Ionization energy decreases

Down a group
-valence electron is farther away and easier to remove

Ionization energy increases

Across a period
-valence electron is held higher