Which of the following has the same number of electrons in its outermost shell and penultimate shell ?

Options

A. Elements with atomic numbers 30,48,80
B. Elements with atomic number 14,15,16
C. Elements with atomic numbers 20,30,50
D. Elements with atomic number 10,18,26

Answer

A

Explanation

Elements with atomic number `30,[Ar]" "3d^(10)4s^(2)`
Element with atomic number `48,[Kr]4d^(10)5s^(2)`
Element with atomic number `80,[Xe]4f^(14)5d^(10)6s^(2)`