Paper 3 Atomic Structure Drills

Q1 Spectral Line Counting

An atom has four energy levels labelled $E_1<E_2<E_3<E_4$. Electrons are excited to $E_4$.

1. Determine the maximum number of different emission lines possible. [2]
2. Explain why not every observed spectrum necessarily shows all possible lines strongly. [2]
3. If $E_4-E_2=4.00\mathrm{eV}$, calculate the wavelength of that transition. Use $hc=1240\mathrm{eV}\mathrm{nm}$. [2]

Q2 Specific Charge

A singly ionised ion has mass $6.64\times 10^{-27}\mathrm{kg}$ and charge $+1.60\times 10^{-19}\mathrm{C}$.

1. Calculate its specific charge. [2]
2. Explain why specific charge is useful when comparing particles. [2]
3. State how the specific charge changes if the same ion loses two electrons instead of one. [1]