Question

What is the difference between a cation and an anion ? Explain with examples.

Answer 1

1. Cation a positively charged ion.	1. Anion is a negatively charged ion.
2. When a neutral atom loses one or more electrons, it develops an overall positive charge and becomes a cation.	2.  When a neutral atom gains one or more electrons, it develops an overall negative charge and becomes an anion.
3. A cation has fewer electrons than the neutral (normal) atom of that element.	3. An anion has more electrons than the neutral (normal) atom of that element.
4. Example: Sodium atom readily loses an electron to form a positively charged sodium ion. Na → Na+ + e−	4. Example: Chlorine atom accepts an electron to become a negatively charged chloride ion. Cl + e− → Cl−
Similarly, calcium atom loses two electrons to become a positively charged calcium ion. Thus, the cation formed has two units of positive charge.  Ca → Ca2++ 2e−	Oxygen atom readily accepts two electrons to become a negatively charged oxygen ion. Thus, the oxygen anion formed has two units of negative charge. O + 2e− → O2−