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
111–120 of 407 · Easy
Question 111
5 marks · Easy
Answer and see the solution →A sample of an element X consists of two isotopes. 30% of the atoms are isotope X-24 (with mass number 24) and 70% are isotope X-25 (with mass number 25). The atomic number of element X is 12.
(a)[3 marks]Calculate the relative atomic mass of element X from its isotopic abundances.
(b)[2 marks]How many electrons are there in an atom of X? State your answer and explain your reasoning.
Question 112
5 marks · Easy
Answer and see the solution →Two atoms of lithium are shown below.
Isotopes of lithium Isotope Mass number Atomic number Number of neutrons 6 3 7 3 (a)[2 marks]Complete the table by calculating the number of neutrons in each isotope.
(b)[2 marks]Describe one way in which the isotopes of lithium are the same, and one way in which they are different.
(c)[1 mark]State the number of electrons in a neutral atom of .
Question 113
5 marks · Easy
Answer and see the solution →An element X has two naturally occurring isotopes: X-64 and X-66. In a sample of X, 75% of the atoms are X-64 and 25% are X-66. The atomic number of X is 30.
(a)[3 marks]Calculate the relative atomic mass of element X. Show all your working.
(b)[1 mark]How many electrons are present in one atom of X?
(c)[1 mark]State the number of electrons in an ion of X with a 2+ charge.
Question 114
5 marks · Easy
Answer and see the solution →Use your knowledge of isotopes and atomic structure to answer the following questions about phosphorus.
(a)[2 marks]Describe two ways in which two isotopes of phosphorus are the same.
(b)[1 mark]Describe one way in which two isotopes of phosphorus are different.
(c)[1 mark]The atomic number of phosphorus is 15. State the number of electrons in a neutral atom of phosphorus.
(d)[1 mark]State the number of electrons in a phosphorus ion with a 3– charge.
Question 115
1 mark · Easy
Answer and see the solution →State what the atomic number of an element represents.
Question 116
3 marks · Easy
Answer and see the solution →Element X has atomic number 9. Use this information to answer the following questions.
(a)[1 mark]Write the electronic configuration for atom X.
(b)[1 mark]How many electrons are in the outermost shell of atom X?
(c)[1 mark]Which period is atom X found in?
Question 117
2 marks · Easy
Answer and see the solution →Rubidium (Rb) has atomic number 37. Calculate the number of protons and electrons in a neutral atom of rubidium.
Question 118
2 marks · Easy
Answer and see the solution →The electronic configuration of an atom is 2,8,5. Explain how you can use this information to work out the group and period of this atom.
Question 119
3 marks · Easy
Answer and see the solution →The table shows the atomic numbers of several elements.
Element Atomic number Lithium 3 Silicon 14 Argon 18 (a)[1 mark]Which element is in Group 1?
(b)[1 mark]Which element is found in Period 3?
(c)[1 mark]Explain how the atomic number of an element helps you decide its position in the Periodic Table.
Question 120
1 mark · Easy
Answer and see the solution →Write the electronic configuration for a calcium atom.