IGCSE Chemistry Paper
Topic 2.2.4: Electronic Configuration & The Periodic Table
Cambridge IGCSE Chemistry (0620) • Papers 2 & 4 Style
Instructions for Candidates
- • Answer all questions in the spaces provided
- • Show all your working clearly - method marks are awarded
- • Use the "Reveal Answer" buttons to check your responses
- • Pay attention to command words: State, Explain, Predict, Calculate
- • Read the Examiner Traps to avoid common mistakes
Section A: Position from Configuration
An element has the electronic configuration 2,8,4.
(a) State which group this element is in.
(b) State which period this element is in.
Element X is in Group VII and Period 2.
(a) Write the electronic configuration of element X.
(b) Identify element X.
(c) State how many electrons element X needs to gain to achieve a full outer shell.
An atom has 11 protons and 12 neutrons.
(a) Write the electronic configuration of this atom.
(b) State which group this element is in.
(c) State which period this element is in.
(d) Calculate the mass number of this atom.
Element Y has the electronic configuration 2,8,8,2.
(a) In which group of the Periodic Table is element Y?
(b) In which period of the Periodic Table is element Y?
An element is in Group VI and Period 3.
(a) Write the electronic configuration of this element.
(b) Name this element.
(c) State the formula of the ion formed by this element.
Section B: Properties from Configuration
Explain why noble gases (Group 0/VIII) are unreactive.
Elements in Group I are very reactive metals. Explain why, in terms of electronic configuration.
Chlorine (Cl) has electronic configuration 2,8,7. Sodium (Na) has configuration 2,8,1.
(a) State the charge on the ion formed by chlorine.
(b) State the charge on the ion formed by sodium.
(c) Explain why chlorine forms this ion.
(d) State the formula of the compound formed between sodium and chlorine.
Carbon has electronic configuration 2,4. Silicon has configuration 2,8,4.
(a) State one similarity in the electronic configurations.
(b) Explain why carbon and silicon are in the same group.
(c) Predict the charge on the ion most commonly formed by silicon.
Element Z has electronic configuration 2,8,8,1.
(a) Predict whether element Z will be a metal or non-metal.
(b) Explain your answer to part (a).
(c) Predict the charge on the ion formed by element Z.
Section C: Reverse Engineering & Application
Element X has electronic configuration 2,8,2. Which group is element X in?
An element forms an ion with charge 2-. The ion has electronic configuration 2,8.
(a) Write the electronic configuration of the atom before it formed the ion.
(b) State which group this element is in.
(c) Name this element.
An element has the following properties: • It is in Period 3 • It forms an ion with charge 3+ • The ion has electronic configuration 2,8
(a) Write the electronic configuration of the atom.
(b) State which group this element is in.
(c) Name this element.
(d) State whether this element is a metal or non-metal.
The table shows information about three elements.
| Element | Electronic Configuration | Group | Period |
|---|---|---|---|
| P | 2,8,7 | ? | ? |
| Q | 2,8,8,2 | ? | ? |
| R | 2,1 | ? | ? |
(a) Complete the table by filling in the missing group and period numbers.
(b) State which element (P, Q, or R) is most reactive.
(c) Explain your choice in part (b).
A mystery element has these properties: • It conducts electricity when solid • It reacts vigorously with water to produce hydrogen gas • It forms an ion with charge 1+ • The ion has the same electronic configuration as neon (2,8)
(a) Write the electronic configuration of the mystery element atom.
(b) State which group this element is in.
(c) State which period this element is in.
(d) Name the mystery element.
(e) Explain why this element forms a 1+ ion.
(f) Write a balanced symbol equation for the reaction with water.
📊 Exam Strategy Tips:
- • Read the question carefully: "State" needs facts only. "Explain" needs reasoning.
- • Show your working: Even if your final answer is wrong, you can earn method marks.
- • Use scientific terminology: "Full outer shell" not "happy atoms".
- • Check electron counts: Protons = Electrons in neutral atoms. Ions have gained/lost electrons.
- • Link to the Periodic Table: Outer electrons → Group number. Number of shells → Period number.
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