Periodic table groups 1-18

group/family one

Alkali metals

group/family two

Alkaline Earth metals

group/family three-twelve

transition metals

group/family thirteen

aluminum

group/family fourteen

carbon

group/family fifteen

nitrogen

group/family sixteen

oxygen

group/family seventeen

halogens

group/family eighteen

noble gases

2 major classifications

metals, non-metals

two names for columns

family, group

two names for rows

periods, series

2 names for elements Boron, Silicon, Germanium, Arsenic, Antimony, and Tellurium

semi-conductor, metalloid

2 elements that occur naturally in liquid

mercury, bromine

2 most reactive elements

francium, fluorine

how many elements are there

115

how many groups

18

how many periods

7

Why are elements in Group 1 and Group 17 highly reactive?

They are one electron away from a full valence shell.

• Group 1 (e.g., K, Rb, Na): Want to lose 1 electron.

• Group 17 (e.g., F, Cl, Br): Want to gain 1 electron.
  This drives strong reactivity.

What happens to atomic radius as you move down a group in the periodic table?

It increases due to the addition of electron shells.

What happens to atomic radius as you move across a period from left to right?

It decreases because of the increasing nuclear charge pulling electrons closer.