Question

The ratio of atomic numbers of two different elements ‘A' and ‘B’ is 1:2. The number of electrons present in the valence shell (3rd) of ‘A’ is equal to the difference in the number of electrons present in the other two shells. Steps involved in the calculation of the ratio of the number of electrons present in a penultimate shell to the Anti-penultimate shell of B are given below. Arrange them in the correct sequence.

• A. 2,3,4,5,1
• B. 2,3,1,5,4
• C. 4,5,2,3,1
• D. 4,2,1,3,5

Answer 1

The correct option is B

2,3,1,5,4

The ratio of atomic numbers of two different elements ‘A' and ‘B’ is 1:2. The number of electrons present in the valence shell (3rd) of ‘A’ is equal to the difference in the number of electrons present in the other two shells. Steps involved in the calculation of the ratio of the number of electrons present in a penultimate shell to the Anti-penultimate shell of B are given below. The correct sequence of steps will be.

1. Calculation of valence electrons present in ‘A'.
2. Calculation of atomic number of ‘A’
3. Calculation of atomic number of ‘B’
4. Writing electronic configuration of ‘B’
5. Calculation of number of electrons present in penultimate and anti penultimate shells of ‘B

Conclusion Statement: Option (b) is the correct answer.