Group 1, Group 7 and Group 0

Group 1 Metals

These are the alkali metals, which are found in group 1 in the periodic table. A highly reactive set of metals that all have 1 electron in their outer shell. Group 1 metals tend to share properties with other metals. Such as being shiny and good conductors of electricity.

Trends in the metals as you go down the group:

  • Melting and boiling pointsdecreases
  • Relative atomic massincreases
  • Reactivity increases

Reactions with group 1 metals:

Group 1 metals react with water to produce hydrogen gas and a metal hydroxide. With the general equation being:

Metal + WaterMetal hydroxide + Hydrogen

An example of this is the reaction of lithium with water to form lithium hydroxide and hydrogen:

Group 1 metals also react with halogens to produce a salt in the general equation:

Metal + HalogenSalt

For example a reaction between the alkali metal sodium and the halogen chlorine to form sodium chloride:

Group 1 metals react with oxygen to form oxides in the general equation:

Metal + OxygenMetal oxide

An example of this is the reaction between sodium and oxygen to form sodium oxide:

Group 7

The elements in this group are called halogens, which are all non-metals.

The table below shows the property of the first five halogens at room temperature.


The trends of these halogens going down the group:

  • Melting and boiling pointincreases
  • Relative atomic mass numberincreases
  • Reactivity decreases
  • Colour – Become darker as you go down the group

Halogens are involved in displacement reactions, in which a more reactive halogen replaces a less reactive halogen. For example, when fluorine reacts with sodium chloride to form sodium fluoride and chlorine:

Fluorine + Sodium chlorideSodium fluoride + Chlorine

As fluorine is lower than chlorine on the periodic table, it is more reactive, which means fluorine displaces chlorine. Another example is:

Chlorine + Sodium bromideSodium bromide + Chlorine

As chlorine is more reactive than bromine, chlorine replaces bromine.

Group 0

Also known as group 8, these elements are called noble gases, they all contain 8 electrons in their outer shell. All of the gases are colourless and unreactive.

When transporting reactive substances, you do not want the atmosphere to be air because the reactive substance can react with oxygen in the air. If you don’t want a reactive substance to react then it is useful packaging it with a noble gas. This is because it wont reactive with the substance you are transporting.

The trends of these noble gases going down the group:

  • Boiling pointincreases
  • Relative atomic mass numberincreases