The energy of the electron in a hydrogen atom can be calculated from the bohr formula:
e= -ry/n^2
in this equation, ry stands for the rydberg energy, and n stands for the principal quantum number of the orbital that holds the electron.
a) calculate the wavelength of the line in the absorption line spectrum of hydrogen caused by the transition of the electron from an orbital with n=2 to an orbital with n=3 . round your answer to significant digits.

Explanation:

Using the Rydberg formula as:

where,

λ is wavelength of photon

R = Rydberg's constant (1.097 × 10⁷ m⁻¹)

n₁ is the initial final level and n₂ is the final energy level

Given that:-

= 3

= 2

Applying in the formula as:

The wavelength of the line in the absorption line spectrum of hydrogen caused by the transition of the electron from an orbital with n=2 to an orbital with n=3 is:-

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

i believe the answer is a.