A, whose position in the Modern Periodic Table is inconsistent by virtue of its properties. Its electronic configuration is similar to that of alkali metals, but it exists as diatomic molecules. B is the element that comes just after sodium in the third period, and belongs to group C in the modern periodic table. Identify A, B and C.

Correct option is A

Sol: The correct answer is (a) A = "Hydrogen," B = "Mg," C = 2

Analyze the given information:

• A: An element with properties inconsistent with its position in the Modern Periodic Table, similar electronic configuration to alkali metals, and exists as diatomic molecules.

  • This description fits hydrogen.

• B: The element just after sodium in the third period.

  • Sodium (Na) is in Group 1 and the third period. The next element is magnesium (Mg).

• C: The group that B belongs to in the Modern Periodic Table.

  • Magnesium (Mg) is in Group 2.

So, the correct identification of A, B, and C is: A: Hydrogen, B: Magnesium (Mg), C: Group 2