An atom has the electronic configuration of `1s^2, 2s^2 2p^6, 3s^2 3p^6 3d^10 , 4s^2 4p^5`. Its atomic weight is 80.its atomic number and the number of neutrons in its nucleus shall be

Options

A. 35 and 45
B. 45 and 35
C. 40 and 40
D. 30 and 50

Answer

A

Explanation

`""_(35)Br^(80)=1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(2)4p^(5)`
A = 80, Z = 35, N = ?
`N=A-Z=80-35=45`
Atomic number (Proton) is 35 and no. of neutron is 45.