Question

In $Cu(At.No.29)$

• A. $13$ electrons have spin in one direction and $16$ electrons in other direction
• B. $14$ electrons have spin in one direction and $15$ electrons in other direction
• C. One electron can have only spin in the clockwise direction
• D. None of the above is correct

Answer 1

The correct option is A $13$ electrons have spin in one direction and $16$ electrons in other direction

${}_{29}Cu=[Ar{]}^{18}3d^{10}4s^1$

All electrons are paired except $4s^1$. Hence $14e^{-}$ have spin one direction and $15e^{-}$ in the other.