Explaining reactivity
The Group 1 elements have similar properties because of the electronic structure of their All elements are made of atoms. An atom consists of a nucleus containing protons and neutrons, surrounded by electrons. – they all have one Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons. in their outer shell.
Explaining trends [Higher tier only]
In a reaction, an atom of a Group 1 element will form an Electrically charged particle, formed when an atom or molecule gains or loses an electron/electrons. with a single positive charge. For example, for sodium forming a sodium ion:
Na → Na+ + e–
A change like this, where an electron is lost, is an example of The gain of oxygen, or loss of electrons, by a substance during a chemical reaction..
The ions formed have a stable electronic structure, like a A chemical element that is odourless, colourless and generally unreactive. from Group 0.
The reactivity of Group 1 elements increases as you go down the group because:
- the atoms get larger
- the outer electron gets further from the nucleus
- the attraction between the nucleus and outer electron gets weaker – so the electron is more easily lost