Question

Write down all the four quantum number for :

$19th$ electron of ${}_{24}\text{Cr}$

• A. $n=3,l=2,m=+2or-2,s=+\frac{1}{2}$ or $-\frac{1}{2}$
• B. $n=4,l=0,m=0,s=+\frac{1}{2}$ or $-\frac{1}{2}$
• C. $n=4,l=2,m=+2or-2,s=+\frac{1}{2}$ or $-\frac{1}{2}$
• D. $n=4,l=1,m=+1or-1,s=+\frac{1}{2}$ or $-\frac{1}{2}$

Answer 1

Answer: (B)

$n=4,l=0,m=0,s=+\frac{1}{2}$ or $-\frac{1}{2}$

The 19th electron for ${}_{24}\text{Cr}$ belongs to 4s subshell.

All the four quantum no.for $19th$ electron of ${}_{24}\text{Cr}$ are $n=4,l=0,m=0,s=+\frac{1}{2}$ or $-\frac{1}{2}$.

Hence the correct option is B.