Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Atomic Structure
108 practice questions
Topics covered
Practice questions
51–60 of 108
Question 51
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 52
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 53
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 54
2 marks · Normal
Answer and see the solution →An atom of sodium-23 () has how many neutrons?
Question 55
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 56
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 57
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 58
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 59
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 60
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