Academic Chemistry

Class NotesApril 9, 2015

Periodic Trends of the

Elements

Atomic Radius - the size of an

atom. Increases to the left and down on the

periodic table.

Electron levels are added as you go down a group.

(atomic size increases)

The nuclear charge increases as you go

across a period toward the right.

(atomic size decreases)

Ionic Radius

The negative ion (anion) is always larger than the neutral atom.

The positive ion (cation) is always smaller than the

neutral atom.

Electronegativity - the force of

attraction an atom has for the

electrons shared in a chemical bond

Ionization Energy - the energy required to remove the first

electron from a neutral gaseous

atom.

The radioactive elements in any

group are generally found at the bottom

of the periodic table.