Which elements have electron configurations that end in ns2np5?

A) noble gases

B) transition metals

C) halogens

D) inner transition metals

The halogens have electron configurations that end in ns2np5.

Explanation:

Halogen: The elements of group 17 of periodic table are halogens like F, Cl, Br, I etc. They have 7 valence shells electrons. The electronic configurations of each halogen is given as follow

F = [He]2s∧2 2p∧5 Cl = [Ne] 3s∧2 3p∧5 Br = [Ar] 4s∧2 3d∧10 4p∧5 I = [Kr]5s∧2 4d∧10 5p∧5

From electronic configurations, it is cleared only halogens have valence shell elctrons in ns∧2 np∧5.

Transition elements: In transitions elements, electronic configuration ended in d - orbital.

Inner transition elements: In transitions elements, electronic configuration ended in f - orbital.

Nobel gases: Nobel gases elements have complete valence shells, Eight electrons like this ns2np6.