Question

Among the following, the orbital that has the lowest energy is________.

• A. $5f$
• B. $4f$
• C. $6s$
• D. $6p$

Answer 1

Answer: (C)

$6s$

$E\propto (n+l)...$Aufbau's rule

$(n+l)$ for $5f,4f,6s,6p$ are $(5+3),(4+3),(6+0),(6+1)$ i.e., $8,7,6,7$ respectively.

Thus $6s$ has the lowest energy among these.