Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Atomic number and mass number
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →An atom of magnesium has atomic number 12 and mass number 25.
Calculate the number of neutrons in this atom. Show your working.
Question 12
3 marks · Normal
Answer and see the solution →Explain the difference between the atomic number and the mass number of an atom. Give an example of each.
Question 13
4 marks · Normal
Answer and see the solution →The table below shows information about three atoms.
Properties of three atoms Atom Atomic number Mass number A 6 14 B 8 16 C 11 23 (a)[2 marks]For atom A, state the number of protons, neutrons and electrons (assuming atom A is neutral).
(b)[2 marks]Which atom in the table has the greatest number of neutrons? Show your reasoning.
Question 14
1 mark · Normal
Answer and check →Which statement about isotopes is correct?
- A.Isotopes have different numbers of protons but the same number of neutrons.
- B.Isotopes have the same number of protons but different numbers of neutrons.
- C.Isotopes have different atomic numbers but the same mass number.
- D.Isotopes have different numbers of electrons only.
Question 15
2 marks · Normal
Answer and see the solution →Name the three types of sub-atomic particles in an atom and state where each is located.
Question 16
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 17
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 18
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 19
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.