Plz help me id really appreciate it.

For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

Which statement best describes the relationship between period and frequency of light waves? a) in wave b the period increases and the frequency decreases from wave a. b) in wave a the period increases and the frequency decreases from wave b. c) in wave b the period is shorter and the frequency is greater than in wave a. d) in wave a the period is shorter and the frequency is greater than in wave b.

Compare and contrast the bohr model and the electron cloud models of the atom.