Column A
1.
Ca becoming Ca+2
:
Ca becoming Ca+2
2.
Cl2 becoming Cl-1
:
Cl2 becoming Cl-1
3.
N2 becoming N-3
:
N2 becoming N-3
4.
Na becoming Na+1
:
Na becoming Na+1
Column B
a.Oxidation
b.Reduction
Column A - Column B
1. Ca becoming Ca+2 : a. Oxidation
In this process, calcium atom loses two electrons to become a calcium ion with a charge of +2.
2. Cl2 becoming Cl-1 : b. Reduction
When molecular chlorine (Cl2) is converted to chloride ion (Cl-1), each chlorine atom gains one electron.
3. N2 becoming N-3 : b. Reduction
In this case, each nitrogen atom (in the nitrogen molecule N2) gains three electrons to become an ion with a charge of -3.
4. Na becoming Na+1 : a. Oxidation
Here, a sodium atom loses one electron to become a sodium ion with a charge of +1.