Question

which of the following sublevels has the highest energy?
a 4s
b 3p
c 3s
d 3d

Explanation:

The energy of sub - levels is determined by the (n + l) rule, where n is the principal quantum number and l is the angular momentum quantum number (s: l = 0, p: l = 1, d: l = 2). For 4s, n + l=4 + 0 = 4; for 3p, n + l = 3+1 = 4; for 3s, n + l=3 + 0 = 3; for 3d, n + l=3 + 2 = 5. Higher (n + l) values correspond to higher energy. When (n + l) values are equal, the sub - level with higher n has higher energy. Since 3d has the highest (n + l) value among the options.

Answer:

d. 3d