Ions (Radicals) and Its Types

In chemistry, ions or radicals are atoms or groups of atoms that carry an electric charge. This charge results from the loss or gain of electrons, which creates either a positive or negative charge. Ions are fundamental components of ionic compounds and play a critical role in chemical reactions, especially in the formation of acids, bases, and salts.

In ionic compounds, there are two components:

1. Cations: Positively charged ions.
2. Anions: Negatively charged ions.

These ions can participate independently in chemical reactions and are therefore called radicals. Depending on their role in forming acids or bases, radicals are categorised as basic radicals or acidic radicals.

1. Basic Radicals

Basic radicals are cations. They pair with anions like hydroxide (OH⁻) to form bases such as sodium hydroxide (NaOH) or potassium hydroxide (KOH). For example, Na⁺, Cu²⁺, NH⁴⁺​. Usually formed when metals lose electrons, e.g., Na⁺, Cu²⁺.

Exceptions: Some non-metallic entities like NH₄⁺^​ (ammonium ion) can also act as basic radicals.

2. Acidic Radicals

Acidic radicals are anions. They combine with the cation H+ to form acids like hydrochloric acid (HCl) or sulphuric acid (H₂SO₄​). For example, Cl⁻, SO₄²⁻​, NO₃⁻.​ Usually formed when nonmetals gain electrons, e.g., Cl⁻.

Exceptions: Complex ions like MnO₄⁻​ (permanganate ion) are also acidic radicals.

1. Simple Radicals: Consist of a single atom with a charge. For example, Na⁺, Cu⁺, and Cl⁻.

2. Composite Radicals: Consist of a group of atoms with a charge. For example, SO₄²⁻​, NH₄⁺​, NO₃⁻.​

Charge and Valency:

• $Na⁺$ has a valency of 1.
• SO₄²⁻​ has a valency of 2.