Question

Define the following terms:

1. Cation

2. Anion

3. Halide

4. Group

5. Period

Answer 1

1. Cation

A cation is a positively charged ion. For example: Mg²⁺, Fe²⁺, CH₃¹⁺ etc. The cation can be any charged ion, whether organic (carbocations) or inorganic (Metal cations). These are attracted towards the cathode during electrolysis.

2. Anion

Opposite of cation is an anion. A anion is a negatively charged ion. For example: Cl^-, Br^-, CN^-, SO₄^2- etc. The anion can be any charged ion, whether organic (carbanion) or inorganic (non metal anions). These are attracted towards the anode during electrolysis. Metals usually form cations while nonmetals usually form anions.

3. Halide

Halide refers to the salt of a compound in which halogen is present in the form of anion. For example NaCl (Chloride of Sodium), MgBr₂ (Bromide of Magnesium), CH₃Cl (Methyl Chloride) etc.

4. Group

The vertical columns down the periodic table are termed as groups. Elements of a group have the same number of valence electrons. For example Group I (Alkaline metals) have 1 valence electron, Group II (Alkaline earth metals) have 2 valence electrons and so on.

5. Period

The vertical rows in the periodic table are known as periods. Elements of a period have same number of unexcited electron energy level. For example Period 1 (H, He) have 1 shell, Period 2 (Li, Be, B, C, N, O, F, Ne) has 2 shells, Period 3 (Na, Mg, Al, Si, P, S, Cl, Ar) has 3 electron shells and so on.