If a hydrogen atom's electron moves from level 1 to level 3, that means a photon with a wavelength of 103 nm impacted the electron. What is the frequency of that photon in Hz? Express your answer in scientific notation.

Using the calculated frequency (Hz) from the previous question, $$2.91\times10^{15}\ Hz$$ ; how much energy (J) does this photon have? Express your answer in scientific notation.

A skier burns about 493 calories per hour of skiing. This is the equivalent of 412,200 J of energy. If a hydrogen atom emits a photon as its electron transitions from energy level 5 to energy level 2, how much energy does that photon have? Express your answer in Joules (J) and in scientific notation.

What is the average atomic mass, or atomic weight, of silicon? Ensure your answer has the correct number of significant figures!

Given the isotopic composition of gallium, find the abundance (in percent) of gallium-71.