When an electron of an atom falls from a higher energy level to the ground state, the atom loses 9.4145 x 10-25 joules of energy. what is the wavelength of the radiation emitted as a result of this transition? (planck’s constant is 6.626 x 10-34 joule seconds; the speed of light is 2.998 x 108m/s)?
0.211 m
1.870 m
4.730 m
4.259 x 107 m
21.106 m

A. 0.211 m
B. 1.870 m
C. 4.730 m
D. 4.259 x 107m
E. 21.106 m

The answer is A. 0.211m

Answerthis solution will not form a precipitateexplanationsolubility equilbrium:         pbf₂(s)  ⇄ pb²⁺(aq) + 2 f⁻(aq)the solubility product expression is    (we exclude solids from the equilibrium expression).now suppose we have the trial ion product q, which we can define as    then, we can interpret  q as the product of the concentration of the ions that we have and ksp as the product of the ion concentrations that are needed to form a saturated solution.if q > ksp, then that implies that there will be a surplus of ions that exceed the amount that is required to form a saturated solution. a precipitate will then form (the precipitate continually  forms until the surplus ions are removed and q is decreased to ksp's value).if q = ksp, the saturated solution that forms is barely saturated and the precipitate will be minimal.if q < ksp, then the ion concentration will not be enough to form a saturated solution (so no precipitate).using our information, we calculate the trial ion product:     since q = 2.7  × 10⁻⁸ < ksp =  4  ×  10⁻⁸, a precipitate will not form.