Question

Which set of quantum numbers given below represents the highest energy of an electron in an orbital?

• A. $n=3,l=0,m=0,s=+\frac{1}{2}$
• B. $n=3,l=1,m=+1,s=+\frac{1}{2}$
• C. $n=3,l=2,m=+1,s=+\frac{1}{2}$
• D. $n=4,l=0,m=0,s=+\frac{1}{2}$

Answer 1

The correct option is C $n=3,l=2,m=+1,s=+\frac{1}{2}$

The energy of an orbital depends upon the sum of values of the principal quantum number (n) and the azimuthal quantum number ( l ). This is called (n +l ) rule.
According to this rule,
In neutral isolated atom, the lower the value of (n + l ) for an orbital, lower is its energy. However, if the two different types of orbitals have the same value of (n +l ), the orbitals with lower value of n has lower energy.
here,
(i)$n+l=3$
(ii)$n+l=4$
(iii)$n+l=5$
(iv)$n+l=4$