Question

The element having 18 electrons in its outermost shell is :

• A. ${}_{28}Ni$
• B. ${}_{46}Pd$
• C. ${}_{29}Cu$
• D. None of these

Answer 1

Answer: (B)

${}_{46}Pd$

The element having 18 electrons in its outer most shell is palladium (atomic number 46).

$1s^2$

$2s^2$

$2p^6$

$3s^2$

$3p^6$

$3d^{10}$

$4s^2$

$4p^6$

$4d^{10}$

In the above configuration, there are 18 electrons in the 4th outer shell (2+6+10=18)

Hence option B is correct.