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 407 · Easy
Question 91
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 92
1 mark · Easy
Answer and see the solution →State the similarity between all isotopes of nitrogen.
Question 93
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 94
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 .
Question 95
1 mark · Easy
Answer and check →State the number of electrons in a neutral atom of lithium, which has an atomic number of 3.
Question 96
3 marks · Easy
Answer and see the solution →(a)[1 mark]State what is meant by the atomic number of an atom.
(b)[2 marks]Draw a table to show the number of electrons in each of the following neutral atoms:
Element Atomic number Beryllium 4 Fluorine 9 Question 97
2 marks · Easy
Answer and see the solution →Calcium has an atomic number of 20. Calculate the number of electrons in a neutral atom of calcium. Show your working.
Question 98
2 marks · Easy
Answer and see the solution →Explain why a neutral atom of aluminium (atomic number 13) also contains 13 electrons.
Question 99
3 marks · Easy
Answer and see the solution →The table below shows the atomic numbers for four elements.
Element Atomic number Phosphorus 15 Sodium 11 Nitrogen 7 Argon 18 (a)[2 marks]For each element, state the number of electrons in its neutral atom.
(b)[1 mark]Explain briefly how you worked out your answers.
Question 100
1 mark · Easy
Answer and check →What is the number of electrons in a neutral atom of silicon, which has atomic number 14?