Question

For which one of the following sets of four quantum numbers,
an electron will have the heighest energy?
n l m s
(a) 3 2 1 1/2
(b) 4 2 –1 1/2
(c) 4 1 0 –1/2
(d) 5 0 0 –1/2

Answer 1

Answer:

The given sets of options are of the form n l m s

Now, by Aufbau's Principle

The electron whose set of quantum numbers has highest value for sum of n+l will be the most energetic electron.

So,clearly option (B) which has 4+2 = 6 value for n+l will be the most energetic electron.

Answer 2

The set of four quantum numbers,  an electron will have the heighest energy are 4 2 –1 1/2

Explanation:

From quantum numbers we can decide the energy of orbital as well as the energy of electron existing in particular orbital.

$n+l$ value can be used to know the energy of orbital

$n+l \propto Energy$

For given sets

(a) $n+l=3+2=5$

(b)$n+l=4+2=6$

(c)$n+l=4+1=5$

(d)$n+l=5+0=5$

Hence the quantum numbers in which electron will have the heighest energy are 4 2 –1 1/2

Hence, the correct answer is option (b)