WJEC Chemistry for AS Level Student Book: 2nd Edition (Draft)

 1.2 Basic ideas about atoms

(c) Successive ionisation energies are a measure of the energy needed to remove each electron in turn until all the electrons are removed from an atom. (i) Write an equation to represent the third ionisation energy of nitrogen. [1] (ii) Explain how successive ionisation energies give evidence for shells and subshells in an atom. [2] 4. Describe the main features of the atomic absorption spectrum of hydrogen. Explain how these features arise and how their interpretation provides evidence for energy levels in the atom. [5] 5. (a) The atomic emission spectrum of hydrogen consists of separate series of lines caused by electrons being excited and falling back down to a lower energy level. When an electron returns from the fifth shell to the second shell, the energy of the radiation emitted is 4.58 × 10 –22 kJ. Calculate the wavelength, in nm, at which the line can be seen. [4] (b) State whether the energy of radiation emitted at a wavelength of 656 nm would be greater or less than 4.58 × 10 –22 kJ. Explain your answer. [1]

31 DRAFT