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
121–130 of 423 · Normal
Question 121
6 marks · Normal
Answer and see the solution →Chlorine exists in nature as two main isotopes: and .
(a)[2 marks]Define the term isotope.
(b)[2 marks]Explain the difference between an atom and a molecule, using chlorine as an example.
(c)[2 marks]Given that the relative abundances of and are 75% and 25% respectively, calculate the relative atomic mass of chlorine. Show your working.
Question 122
6 marks · Normal
Answer and see the solution →A sample contains molecules of ammonia, .
(a)[2 marks]State the meanings of the terms 'atom' and 'molecule'.
(b)[2 marks]Each ammonia molecule contains one nitrogen atom (N) and three hydrogen atoms (H). The nitrogen atom in this molecule has a mass number of 15 and an atomic number of 7. Each hydrogen atom has a mass number of 1 and an atomic number of 1.
i. Calculate the total number of protons in one molecule of ammonia, using your answer to part (a) and the information above.
(c)[2 marks]ii. Calculate the total number of neutrons in one ammonia molecule, using the mass numbers given above.
Question 123
2 marks · Normal
Answer and see the solution →The Periodic Table is organised in columns and rows. State the name given to:
(a)[1 mark]the vertical columns in the Periodic Table.
(b)[1 mark]the horizontal rows in the Periodic Table.
Question 124
4 marks · Normal
Answer and see the solution →The following table shows information about three elements:
Element Atomic number Sulfur 16 Phosphorus 15 Oxygen 8 Use this information to answer the following questions.
(a)[1 mark]State the number of electrons in an atom of phosphorus.
(b)[1 mark]Write the electronic configuration of oxygen.
(c)[1 mark]Write the electronic configuration of sulfur.
(d)[1 mark]State the number of electrons in the outer shell of a sulfur atom.
Question 125
3 marks · Normal
Answer and see the solution →The electronic configuration of element Y is 2,8,2.
Explain the position of element Y in the Periodic Table in terms of its group and period.
Question 126
4 marks · Normal
Answer and see the solution →The table below shows the atomic numbers of four elements:
Element Atomic number Magnesium 12 Potassium 19 Neon 10 Chlorine 17 Based on the data, answer the following questions:
(a)[1 mark]Which element is in Group 0?
(b)[1 mark]Which element is in Group 1?
(c)[2 marks]Which two elements are in Period 3?
Question 127
1 mark · Normal
Answer and check →Which is the correct electronic configuration for an atom of sodium (atomic number 11)?
- A.2,8,1
- B.2,9
- C.2,8,2
- D.2,7,2
Question 128
2 marks · Normal
Answer and see the solution →State the group numbers of the following elements in the first 20 elements:
(a)[1 mark]Fluorine
(b)[1 mark]Magnesium
Question 129
4 marks · Normal
Answer and see the solution →A student writes the following table for three elements.
Element Atomic number Nitrogen 7 Calcium 20 Aluminium 13 Answer the following questions about the electronic configurations of these elements.
(a)[1 mark]What is the electronic configuration for nitrogen?
(b)[1 mark]What is the electronic configuration for aluminium?
(c)[1 mark]Give the electronic configuration for calcium.
(d)[1 mark]Which of these elements has the greatest number of electron shells? Explain your answer.
Question 130
3 marks · Normal
Answer and see the solution →Copper (Cu) and neon (Ne) are two elements found in the Periodic Table.
Copper is found in Group 11 and Period 4. Neon is found in Group 0 and Period 2.
Explain how the information about group and period allows you to deduce the atomic numbers of copper and neon.
(a)[1 mark]State what the group number and period number tell you about an element's position in the Periodic Table.
(b)[1 mark]Using the Periodic Table, deduce the atomic number of neon (Ne).
(c)[1 mark]Using the Periodic Table, deduce the atomic number of copper (Cu).