What could be the reason for the change in reactivity of elements?

What could be the reason for that?

What could be the reason for the less reactivity of noble gases?

What could be the reasons for adopting contraceptive methods?

Give reason for the need of classification of element .

What could be the reason for this variation in burning patterns among combustible materials?

What is the reason for the change in colour of copper sulphate when iron nail is kept on it ?

Obsere the data given in the following table. What could be the reasons for the migration of birds to this lake ?

What are elements?

Discuss the trends in chemical reactivity of group 15 elements