Who showed for the first time that there is periodicity in properties of elements? Why is there periodicity in the periodic table? Explain. [3 MARKS]
Each point: 1 Mark
1. It was Newland’s classification that showed for the first time that there is periodicity in properties of elements.
2. Periodicity in periodic table is due to valence electrons.
3. Elements with same number of valence electron in the outer most shell have similar properties.