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
31–40 of 161 · Hard
Question 31
2 marks · Hard
Answer and see the solution →Helium-3 is an isotope of helium with a mass number of 3. It has 2 protons. State the number of neutrons and electrons in a neutral atom of helium-3.
Question 32
5 marks · Hard
Answer and see the solution →The element chlorine occurs naturally as two main isotopes: chlorine-35 and chlorine-37. The relative abundances of these isotopes are 75% chlorine-35 and 25% chlorine-37.
(a)[1 mark]Define the term 'isotope'.
(b)[1 mark]State the atomic number of chlorine.
(c)[1 mark]Explain, using your knowledge of atomic structure, why chlorine-35 and chlorine-37 are isotopes of the same element.
(d)[2 marks]Calculate the relative atomic mass of chlorine to 1 decimal place. Show your working.
Question 33
2 marks · Hard
Answer and see the solution →State the relative mass and relative charge of a neutron, and explain how these properties compare to those of a proton.
Question 34
2 marks · Hard
Answer and see the solution →A sample of element Q contains 10% of isotope Q-40 and 90% of isotope Q-42.
Calculate the relative atomic mass of Q. Give your answer to one decimal place.
Question 35
5 marks · Hard
Answer and see the solution →(a)[1 mark]Describe what isotopes are.
(b)[3 marks]The element magnesium has isotopes with mass numbers 24, 25, and 26. Give the number of protons and neutrons in each of these isotopes.
Isotope Number of protons Number of neutrons ^24Mg ^25Mg ^26Mg (c)[1 mark]Explain why magnesium-24, magnesium-25, and magnesium-26 all have the same chemical properties.
Question 36
2 marks · Hard
Answer and see the solution →The element X has two stable isotopes: X-64 (mass = 64, abundance = 73%) and X-66 (mass = 66, abundance = 27%).
Calculate the relative atomic mass of X. Give your answer to one decimal place.
Question 37
2 marks · Hard
Answer and see the solution →Sulfur has an atomic number of 16.
Calculate the number of electrons in two neutral atoms of sulfur.
Question 38
5 marks · Hard
Answer and see the solution →The table below gives information about three elements.
Atomic number of elements Element Atomic number A 7 B 12 C 15 (a)[1 mark]State the number of electrons in a neutral atom of element B.
(b)[2 marks]Element C is found in a rock sample containing 5 atoms. Calculate the total number of electrons in all these atoms.
(c)[2 marks]Explain why a neutral atom of element A contains the same number of electrons as its atomic number.
Question 39
2 marks · Hard
Answer and see the solution →Cobalt has an atomic number of 27.
Give the number of electrons in a neutral atom of cobalt and explain your answer.
Question 40
2 marks · Hard
Answer and see the solution →A neutral atom of silver has an atomic number of 47 and a mass number of 108. Calculate the number of electrons and neutrons in this atom.