Chemistry Questions

Find the similarity in the following :

Carbon, Silicon, Boron, Arsenic

The vast amount of sea weeds present in oceans may produce an endless source of

___ is the number of shells for elements of the 3rd period.

By volume, 21% of air is _______________.

An electron loses potential energy when it

____ are atoms/molecules/ions containing the same number of electrons.

Valency of an element depends on which of the following?

I. Number of losing electron

II. Number of gaining electron

III. Number of sharing electron

Plaster of Paris ______.

I. changes into gypsum on mixing with water

II. is CaSO4.2H2O

III. is used for decoration