A student was asked to give the electron configuration for the element Iodine that has 53 electrons. The answer was given as [Ar] 5s2 4d10 5p5 His answer is not correct. Explain

the electron configuration:

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, etc
Ar = [Ne] 3s² 3p⁶ ( 18)
Iodine = 53 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁵

if use Ar (18) ⇒ [Ar] 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁵

if use Kr (36) ⇒ [Kr] 5s², 4d¹⁰, 5p⁵

explanation: no but i do not usually comment

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.