Question

An element has an atomic number of 107. What is its electronic configuration and what will be its group number?

• A. [Rn] 5f¹⁴ 6d¹ 7s² 7p⁴ , group 3
• B. [Rn] 5f¹⁴ 6d⁵ 7s² , group 7
• C. [Rn] 5f¹⁴ 7s² 7p⁵ , group 7
• D. [Rn] 5f¹⁴ 6d² 7s² 7p³ , group 15

Answer 1

The correct option is B

[Rn] 5f¹⁴ 6d⁵ 7s² , group 7

In accordance with Aufbau principle, the most stable electronic configuration is (b) and its group number is 7.

If you look at option (a), 7p electrons are filled without finishing 6d.
If you look at option (b), 7p electrons are filled without even starting to fill the 6d
Figure out option (d) on your own.