Question

Calcium reacts with oxygen to form calcium oxide (CaO)
1. Which atom in it loses electron?
2. Which atom in against electron?
3. What is the valency of calcium?​

Answer 1

1) calcium

2) oxygen ( gains)

3) +2

Answer 2

Answer: The answers are 1) Calcium atom loses its electron

2)Oxygen atom gains electrons and

3) the valency of Calcium in the compound CaO is 2

Explanation:

This reaction is an example of a combination reaction

             $2Ca +O_{2}$  → $2CaO$

The electronic configuration of Calcium  is $1s^{2}2s^{2} 2p^{6} 3s^{2}3p^64s^{2}$

The electronic configuration  of Oxygen is 8  is $1s^{2}2s^{2}2p^{4}$

When Calcium reacts with oxygen to form calcium oxide, in order to achieve octet Calcium loses its 2 electrons to form a Calcium ion

                                    $Ca$ →$Ca^{2+} + 2e^{-}$

Whereas Oxygen gains two-electron to form Oxygen ion $O + 2e^{-}$→ $O^{2-}$

• So the valency of Calcium and Oxygen in CaO is 2