Anybody know number 7 ? Please help !!

ur answer would be b hope i let me know if it is right

if two electrons have the same n, the same ℓ, and the same ml, then they are in the same orbital. the pauli exclusion principle states that no two identical fermions (a fancy word for electrons and other subatomic particles like electrons) may occupy the same quantum state in an atom simultaneously.

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.

it's c. elements are placed in rows based on how may valencies electrons have.