Question

Elements after atomic number $103$ have not been discovered till now. If an element with atomic number $106$ were ever discovered which of the following electronic configuration will it possess.

• A. $\left[Rn\right]5f^{14}6d^{4}7s^1$
• B. $\left[Rn\right]5f^{14}6d^{5}7s^1$
• C. $\left[Rn\right]5f^{14}6d^{6}7s^0$
• D. $\left[Rn\right]5f^{14}6d^{1}7s^{2}7p^3$

Answer 1

The correct option is A $\left[Rn\right]5f^{14}6d^{4}7s^1$

Rn electronic configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}4f^{14}5d^{10}6s^{2}6p^6$ . Atomic number of Redon is 86.

According to Aufbau Principle extra electrons will be filled in order of$7s5f6d7p$

so remaining electrons may be filled as $7s^{2}5f^{14}6d^{4}7p^0$

while $7s^{1}5f^{14}6d^{5}7p^0$ this configuration is more stable because of half-filled d-orbital.

so electronic configuration for 106 atomic number is $\left[Rn\right]5f^{14}6d^{5}7s^1$