Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Relative atomic mass
19 practice questions
Practice questions
1–8 of 8 · Easy
Question 1
1 mark · Easy
Answer and see the solution →Naturally occurring boron is made up of two isotopes: 20% of its atoms have a mass number of 10, and the rest have a mass number of 11. What is the relative atomic mass of boron to the nearest whole number?
Question 2
3 marks · Easy
Answer and see the solution →The element oxygen has three naturally occurring isotopes: ^{16}O, ^{17}O and ^{18}O.
(a)[1 mark]State what is meant by the term 'isotope'.
(b)[1 mark]State one thing that all isotopes of oxygen have the same.
(c)[1 mark]State one way in which isotopes of oxygen differ.
Question 3
2 marks · Easy
Answer and see the solution →A sample of element Y contains 75% of isotope ^{24}Y and 25% of isotope ^{25}Y. Calculate the relative atomic mass of Y. Give your answer to one decimal place.
Question 4
2 marks · Easy
Answer and see the solution →Explain why isotopes of calcium all react in the same way, even though they have different numbers of neutrons.
Question 5
3 marks · Easy
Answer and see the solution →The table shows the isotopes of element Z and their percentage abundances:
Isotopes of Z Isotope Relative Mass Percentage Abundance Z-31 31 60 Z-32 32 40 (a)[2 marks]Calculate the relative atomic mass of Z. Give your answer to one decimal place.
(b)[1 mark]Which isotope of Z is most abundant?
Question 6
1 mark · Easy
Answer and see the solution →State the similarity between all isotopes of nitrogen.
Question 7
3 marks · Easy
Answer and see the solution →Below is information about two isotopes of lithium: Isotope 1: ^{6}Li, abundance 8%. Isotope 2: ^{7}Li, abundance 92%.
(a)[1 mark]Write the equation for calculating the relative atomic mass of lithium using these data.
(b)[2 marks]Calculate the relative atomic mass of lithium to one decimal place.
Question 8
2 marks · Easy
Answer and see the solution →A sample contains atoms of oxygen-16 () and oxygen-18 (). Both are isotopes of oxygen.
State the number of protons and the number of neutrons in an atom of .