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1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes

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Question 7
H

Element R has an atomic number of 31. Element R has two isotopes, with mass numbers of 69 and 71. In a sample of element R, the number of atoms with mass number 69 and the number of atoms with mass number 71 are in the ratio 13:713 : 713:7.

a.

Calculate the relative atomic mass of element R. Give your answer to three significant figures.

[3]
b.

Explain why the relative atomic mass of element R is closer to 69 than to 71.

[1]
c.

Give the number of neutrons in an atom of each isotope of element R.

[2]
Markscheme

1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes Questions

  1. GCSE
  2. /Chemistry
  3. /1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes

40 exam-style questions on AQA GCSE Chemistry 1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes, covering 1.1.1a Atoms, elements and compounds, 1.1.1b Half equations and ionic equations, 1.1.2 Mixtures, 1.1.3 The development of the model of the atom (common content with physics), 1.1.4 Relative electrical charges of subatomic particles, 1.1.5 Size and mass of atoms, 1.1.6 Relative atomic mass, and 1.1.7 Electronic structure. Each one has a worked solution and a mark scheme showing where the marks go.

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