Alkali Metals

Halogens

Properties

Trends

Properties

Alkali Metals are very soft, and they can be cut with even a plastic knife.

All Alkali Metals are shiny

They are very reactive

They all have 1 electron in their outermost shell

Low melting points

All elements have low density

Can easily be ionized, they always form positive ions.

As you go down the group...

Atomic Number Increases

Electronic Shells increases

Reactivity of elements increases

Atomic Radii increases

Ionization energy decreases

Electronegativity decreases

Melting and Boiling points decreases

Density Increases

All Halogen molecules naturally occur as diatomic molecules (2 atoms of the same halogen element make up the molecule)

They are highly reactive

They all have 7 electrons in their outermost shell

They form negative ions, and these elements can be easily ionized.

These elements are poor conductors of electricity and heat

These elements are great conductors of electricity and heat

These elements are used to make salts

All Halogens have a pungent and often nasty smell

The halogen elements are extremely toxic

Trends

As you go down the group...

Atomic Number increases

Electronic Shells increases

Atomic Radii increases

Ionization energy increases

Reactivity of elements decreases

Melting and Boiling points increases

Electronegativity decreases

Electron Affinity decreases