1What is an ion? Give examples.
2Why is an atom electrically neutral?
3Write three differences between a cation and an anion.
4How does a magnesium atom (2, 8, 2) become a \( \text{Mg}^{++} \) ion? What is its valency?
5What kind of ion does an oxygen atom (2, 6) form? Explain.
6Write the symbol and valency of these ions: ammonium, sulphate, phosphate, ferric, hydroxide.
7What is the difference between the cuprous and cupric ions?
8How many protons and electrons does a sodium ion have? Where does its charge come from?