To which group do the alkaline earth metals such as radium, barium and strontium belong?

Correct option is B

Correct Answer: (b) Group 2A
The elements Radium (Ra), Barium (Ba), Strontium (Sr), Calcium (Ca), Magnesium (Mg), and Beryllium (Be) belong to Group 2A of the Periodic Table. These are known as Alkaline Earth Metals due to their basic (alkaline) nature and presence in Earth's crust.
Key Characteristics of Alkaline Earth Metals (Group 2A):
Valency: 2 (They form +2 cations by losing two electrons).
Highly Reactive: React with water, but less reactive than Group 1A alkali metals.
Low Density: Lighter than most transition metals but denser than alkali metals.
High Melting & Boiling Points: Higher than Group 1A metals due to stronger metallic bonding.
Soluble Salts: Their compounds like calcium carbonate (CaCO₃) and magnesium sulfate (MgSO₄) are widely found in nature.

Information Booster: 
The Periodic Table is a systematic arrangement of chemical elements based on their atomic number, electron configuration, and chemical properties. It was first developed by Dmitri Mendeleev in 1869 and later refined to its modern form.
Key Features of the Periodic Table
1. Structure of the Periodic Table
● Groups (Vertical Columns): 18 groups, elements in the same group share similar chemical properties.
● Periods (Horizontal Rows): 7 periods, arranged by increasing atomic number.
● Blocks: s-block, p-block, d-block, and f-block, based on electron configuration.
2. Major Element Groups & Their Characteristics
1. Alkali Metals (Group 1A) – Highly Reactive
● Includes: Lithium (Li), Sodium (Na), Potassium (K), etc.
● Properties: Soft, low density, react violently with water.
2. Alkaline Earth Metals (Group 2A) – Less Reactive
● Includes: Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba).
● Properties: Harder, denser, and react moderately with water.
3. Transition Metals (Groups 3-12) – Strong & Conductive
● Includes: Iron (Fe), Copper (Cu), Zinc (Zn), Silver (Ag), Gold (Au).
● Properties: High melting points, good conductors of electricity.
4. Halogens (Group 17) – Highly Reactive Non-Metals
● Includes: Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I).
● Properties: Form salts with metals, used in disinfectants.
5. Noble Gases (Group 18) – Inert Gases
● Includes: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr).
● Properties: Non-reactive, used in lighting and cooling systems.