Question

The correct set of four quantum numbers for the valence electrons of Rb (Z = 37) is:

• A. 5, 0, 0, + $\frac{1}{2}$
• B. 4, 1, 0, + $\frac{1}{2}$
• C. 5, 1, 1, + $\frac{1}{2}$
• D. 6, 0, 1, + $\frac{1}{2}$

Answer 1

The correct option is A 5, 0, 0, + $\frac{1}{2}$

We can break 37 in its shells ( K, L, M...) as 2 + 8 + 8 + 18 + 1
Since 'n' can be thought of as the shell number, we can see that 'n' value is 1.
This is goint to be an s block element since there is only 1 electron in the last shell.
This gives us the other quantum numbers to be 0 as well.
The spin quantum number value can be + or - $1/2$