Calcium is an element with atomic number 20. Stating reason answer each of the following questions:
- Is calcium a metal or non-metal?
- Will its atomic radius be larger or smaller than that of potassium with atomic number 19?
- Write the formula of its oxide.
Answer:
- Calcium is a metal since it has two electrons in its outermost shell which it can lose easily.
- K(19) is placed before Ca(20) in the same period (fourth period). Since the atomic radius decreases along a period, the atomic radius of calcium is smaller than that of potassium.
- The formula of oxide of calcium is CaO, because the valency of calcium as well as that of oxygen is 2.