Question

Maximum number of electrons possible with spin quantum number \(+\frac{1}{2}\) and principal quantum number \(n = 4\) in an atom is:

• A. 16
• B. 9
• C. 4
• D. 25

Hint:

Each orbital holds 2 electrons with opposite spins. So, for spin \(+\frac{1}{2}\), take half of the shell's full capacity: \(n = 4 \Rightarrow 16\).

Answer 1

The Correct Option is A

Maximum number of electrons in a shell is given by: \[ 2n^2 \Rightarrow 2 \cdot 4^2 = 32 \] Out of these, half will have spin \( +\frac{1}{2} \): \[ \frac{32}{2} = 16 \]