Is solar eclipse a periodic change? Give your reason.

Ionisation energy decreases down the group in periodic table. Give reason .

(a) Wriite any three uses of copper. (b) Ionisation energy decreases down the group in periodic table. Give reason.

Growing of nails is a periodic change. Why?

State two examples of periodic changes.

Predict which of the following hydrides is a gas on a solid (a) HCI (b) NaH. Give your reason.

The number of elements in the first period is only 2. Give reason.

_________ is an example of a periodic change.