Chemistry Exam Q Help? :)

yoyojc

Hi, so I'm working my way through Chemistry exam papers and thankfully doing l ok what we've done so far.. However one thing that keeps getting me is the study of spectra chapter, I mean I get it, it's not that difficult to comprehend but this question (which came up in a Christmas exam) is really difficult for me to understand. Would anyone be able to ask it in a really simple way? It would be better for me to understand the question than to just be learning off a sample answer.. thanks

2013 Q5 (b) Use Bohr’s atomic theory of 1913 to account for the emission spectrum of the hydrogen atom. (15)
Explain, in terms of atomic structure, why different flame colours are observed in flame tests using salts of different metals.

Thank you!

yoho139

Marking scheme, page 10.

Parts in bold are the answer, things in (brackets) are explanations and the [square brackets] show point breakdown.

Bohr theorised that each electron orbiting a hydrogen atom has a discrete (ie fixed amount) of energy. [3 marks]
Normally, these occupy the lowest available orbital (ie they would stay in the 1s orbital), called the ground state. [3 marks]
When energy is supplied to the atom through heat, for example, the electrons jump to a higher orbital and therefore have more energy (eg they jump to the 2s orbital). This is the excited state. [3 marks]
The excited state is unstable, so the electron falls back to the ground state. (self explanatory) [3 marks]
The electron falls back to the ground state for stability. The energy difference between the states divided by Planck's constant gives the frequency of the photon emitted by the electron. (this is a word description of E2-E1=hf. You can put that down and explain what each part is, if you want) [3 marks]

Every element has a unique electron configuration. [3 marks]
Therefore, the energy differences in each case will be different, producing different colours. [3 marks]

Tell me if you'd like any of that clarified.

yoyojc

Thank you