Solid

Liquid

Gas

They are all unreactive

They exist as gases

They are monoatomic molecules

They are diatomic molecules

The BP and MP both decrease

The BP and MP both increases

The BP increases but the MP decreases

The BP decreases but the MP increases

They are soft and can be cut with a knife

They corrode rapidly when exposed to oxygen in the air

They produce an acidic solution when reacted with water

They produce hydrogen when reacted with water

Metallic character

Number of electron shells

Number of outer electrons

Tendency to form positive ions

elements in the same period have the same number of outer electrons

the elements on the left are usually gases

the most metallic elements are on the left

the relative atomic mass increases from right to left