A) based on the spectrum, (i) write the ground-state electron configuration of the element, and (ii) identify the element. (b) calculate the wavelength, in meters, of electromagnetic radiation needed to remove an electron from the valence shell of an atom of the element.

Question: The question is incomplete. The spectrum was not added to the question. Find attached of the spectrum

(A)

(i)  1s²   2s²   2p⁶   3s²    3p⁶    4s²

(ii) Calcium

(B) Wavelength = 2.03*10^-7 m

Explanation:

A)

(i)  from the spectrum, the electron configuration can be written as;

1s²   2s²   2p⁶   3s²    3p⁶    4s²

(ii) from the electron configuration, the element has 20 number of electron.

Therefore, the element is calcium.

(b)Calculating the wavelength using he formula;

λ = h*c/ΔE

where;

h = 6.626*10^-34

c = 3*10^8

ΔE = 0.980*10^-18

Substituting , we have;

λ = h*c/ΔE

  = (6.626*10^-34 *  3*10^8)/ 0.980*10^-18

  = 1.9878*10^-25/0.980*10^-18

  = 2.03*10^-7 m

pure substance: iron,copper

impure substance: water,charcoal

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation: