Calcium is an element with atomic number 20. Stating reason answer each of the following questions: (i) Is calcium a metal or non-metal ? (ii) Will its atomic radius be larger or smaller than that of potassium with atomic number 19 ? (iii) Write the formula of its oxide.

Calcium is an element with atomic number 20. Stating reason answer eac

1.	Calcium is an element with atomic number 20. Stating reason answer each of the following questions: (i) Is calcium a metal or non-metal ? (ii) Will its atomic radius be larger or smaller than that of potassium with atomic number 19 ? (iii) Write the formula of its oxide.
Answer» Solution :(i) CALCIUM is a metal. The oxide of calcium `viz`., `CaO` is a basic oxide because it dissolves in water to give a base alkali). `2Ca +O_(2) to 2 CaO` `CaO + H_(2) O tounderset("Calcium hydroxide")( Ca (OH)_(2))` (ii) Atomic RADIUS of Ca is smaller than that of K. This is because, the next electron enters the same orbit as that of the last electron of K. Electronic configuration of K : 2, 8, 8, 1 Electronic configuration of Ca : 2, 8, 8, 2 And because of the increased nuclear CHARGE, the electrons in the last orbit are attracted with a greater FORCE resulting in the decrease of atomic radius. (iii) CaO is the formula of oxide of calcium.