91Ó°ÊÓ

According to Bohr's model, is energy absorbed or released when an electron moves to a shell of lower \(n\) ?

According to Bohr's model, energy must be put into an atom to move an electron from a low-energy shell to a higher-energy shell. How do you calculate the amount of energy needed for the move?

Use electron configuration notation to explain why aluminum, Al, and gallium, Ga, have similar chemical properties even though gallium has \(d\) electrons but aluminum does not.

Which subshell is filled in transition metals? What is unique about its order of filling?

Why is the formula for calcium sulfide \(\mathrm{CaS}\) and not \(\mathrm{Ca}_{2} \mathrm{~S} ?\)

Select the element from each pair expected to have the lower first ionization energy. Explain. (a) \(\mathrm{N}\) and \(\mathrm{F}\) (b) \(\mathrm{Mg}\) and \(\mathrm{Ba}\) (c) \(\mathrm{N}\) and \(\mathrm{Ca}\)

How does the first ionization energy of the alkali metal in a given period compare with the first ionization energy of the halogen in the same period? What is the result in terms of how these elements tend to react with each other?

Arrange calcium, strontium, arsenic, bromine, and chlorine in order of (a) increasing atomic size and (b) increasing first ionization energy.

Predict the formula for lithium nitride, made from lithium, \(\mathrm{Li}\), and nitrogen, \(\mathrm{N}\). Explain your reasoning.

Suppose the 3s valence electron in a ground-state sodium atom is excited to the 4 s orbital. Why does the electron now have higher energy?