1What are a valence shell and valence electrons? Use sodium as an example.
2Define valency.
3What is the octet rule?
4Why is the valency of neon 0?
5Oxygen has 6 valence electrons, so why is its valency 2?
6Write the electron arrangement of aluminium, atomic number 13, and find its valency.
7Which is more reactive, sodium or magnesium? Why?
8What is variable valency? Give two examples.