Group 1 (I) – The alkali metals
The first vertical column of elements in the periodic table, starting with lithium and ending with francium. Also called the alkali metals. elements have similar physical and chemical properties because they all have one electron in the outer shell of their atoms.
- low density. The first three – lithium, sodium and potassium – are less dense than water and therefore float on water.
- very soft. They are easily cut with a knife.
- shiny when first cut, but tarnish rapidly in air.
- low melting points. The The temperature at which a solid changes into a liquid as it is heated. decrease as the atoms get bigger going down the group.
