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

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

the answer your looking for is c).