Question

Which of the given elements A, B, C, D and E with atomic number $2,3,7,10\mathrm{and}30$ respectively belong to the same period?

• A. A, B, C
• B. B, C, D
• C. A, D, E
• D. B, D, E

Answer 1

The correct option is B

B, C, D

Explanation for correct option:

B. B, C, D

• The element with an atomic number $2$ is Helium$\left(\mathrm{He}\right)$ which belongs to Group-$18$ and the first period.
• The element with an atomic number $3$ is Lithium$\left(\mathrm{Li}\right)$ and it belongs to Group-$2$ and the second period.
• The element with an atomic number $7$ is Nitrogen$\left(\mathrm{N}\right)$ and it belongs to Group-$15$ and the second period.
• The element with an atomic number $10$ is Neon$\left(\mathrm{Ne}\right)$ and it belongs to Group-$18$ and the second period.
• The element with an atomic number $30$ is Zinc$\left(\mathrm{Zn}\right)$ which belongs to Group-$12$ and the fourth period.

Thus, the elements that belong to the same period i.e. the second period are Lithium, Nitrogen, and Neon, and they are denoted as B, C, and D as per the question.

Explanation for incorrect options:

The given elements B, C, and D belongs to the same period. Thus options A, C, and D are incorrect.

Hence, the correct option is B i.e. B, C, and D