Question

Quantum numbers $n=3,l=1,ml=0,ms=\pm 1/2$ are given. It represents the last electron to be added to complete the ground state electron configuration of an element. Which of the following could be the symbol of this element?

• A. $Na$
• B. $Si$
• C. $Th$
• D. $V$
• E. $Zn$

Answer 1

Answer: (B)

$Si$

Quantum numbers are $n=3$, $l=1$, $m_l=0$, $m_s=\pm 1/2$. This set of quantum numbers represents the last electron to be added to complete the ground state electron configuration of an element. From the quantum numbers, we can say that the last electron enters 3p orbital. The quantum number l with value 1 corresponds to p orbital. The symbol of the element could be Si. The electronic configuration of Si is $1s^{2}2s^{2}2p^{6}3s^{2}3p^2$