Question

which of the given elements A,B,C,D,E with atomic number 2,3,7,10, and 30 respectively belongs to the same period ?
a.A,B,C. b. B, C, D c.A,D,E d.B,D,E​

Answer 1

Answer:

At no. of elements a,b,c,d,e are 2,3,7,10,30. Elements b , c , d belongs to the same period because the no. of valence shells are all 2

Answer 2

Answer:

answer is b.B,C,D

Explanation:

in one period thera are 18 elements and 3,7&10 belongs to 2 period