Question

Which of the given elements A, B, C, D and E with atomic number $2,3,7,10$ 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

Answer: (B)

B, C, D

The first period contains $2$ elements. The second period contains $8$ elements. The third period contains $8$ elements. Therefore, the first period contains $1-2$ atomic number. The second period contains $3-10$ atomic number. The third contains $11$ to $18$ atomic number. The fourth period contains $19$ to $36$ atomic number.

So B, C, D belong to the same period.

Hence, the correct option is $\text{B}$