Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
91–100 of 423 · Normal
Question 91
4 marks · Normal
Answer and see the solution →An atom of lithium has atomic number 3 and mass number 7.
(a)[1 mark]State what the atomic number tells you about the atom.
(b)[2 marks]Explain how to calculate the number of neutrons in this atom and give the answer.
(c)[1 mark]Lithium has isotopes. Define 'isotope'.
Question 92
2 marks · Normal
Answer and see the solution →State the number of protons and the number of neutrons in an atom of magnesium-25 ().
Question 93
4 marks · Normal
Answer and see the solution →Use the information below to answer the questions about isotopes.
(a)[1 mark]Give the definition of isotopes.
(b)[2 marks]State one similarity and one difference between the isotopes and .
(c)[1 mark]Explain why the chemical properties of the two isotopes are the same.
Question 94
3 marks · Normal
Answer and see the solution →Bromine consists of two isotopes: and . The percentage abundances are 51% and 49% respectively. Calculate the relative atomic mass of bromine. Give your answer to 1 decimal place.
Question 95
3 marks · Normal
Answer and see the solution →Chlorine exists mainly as two isotopes, and . The Periodic Table gives chlorine a relative atomic mass of 35.5.
Explain why this value is not a whole number. Your answer should refer to isotopes and how the value is calculated.
Question 96
4 marks · Normal
Answer and see the solution →The table shows the abundances of three isotopes of element X.
Isotope Relative Mass % Abundance X-10 10 20 X-11 11 50 X-12 12 30 Question 97
1 mark · Normal
Answer and check →Which statement correctly describes all isotopes of an element?
- A.They have the same mass number but different atomic numbers.
- B.They have the same number of protons but different numbers of neutrons.
- C.They have different chemical properties.
- D.They contain the same number of neutrons.
Question 98
2 marks · Normal
Answer and see the solution →An atom of sodium-23 () has how many neutrons?
Question 99
4 marks · Normal
Answer and see the solution →Consider two isotopes of carbon: and .
(a)[1 mark]State the number of protons and neutrons in .
(b)[1 mark]State the number of protons and neutrons in .
(c)[1 mark]Explain why and are considered isotopes of the same element.
(d)[1 mark]Describe one way in which the two isotopes differ.
Question 100
2 marks · Normal
Answer and see the solution →State the number of electrons in:
(a)[1 mark]an atom of magnesium (atomic number = 12)
(b)[1 mark]an atom of phosphorus (atomic number = 15)