Question

The electronic configuration of an element M is 2, 8, 2. In modern periodic table, the element M is placed in

• A. 4th group
• B. 2nd group
• C. 14th group
• D. 18th group

Answer 1

Answer:

B. 2nd group

• The number of shells equals the period number of that element.
• The number of valence electrons indicates the group of that element.

Example:

• Electronic Configuration of Oxygen – 2, 6
• It has 2 shells and 6 valence electrons. So it belongs to 2nd period and 6th group.

Note:

• In the question given that, the electronic configuration is 2,8,2.
• It has 3 shells and 2 valence electrons. So it belongs to 3rd period and 2nd group.
• In modern periodic table, the element M is placed in 3rd period and 2nd group.