Ion Formation: Past Paper Practice
15 Questions • Definitions, Electronic Configurations & Charge Explanations
EXAMINER TRAPS - Watch Out!
- ✗Cation ≠ "Positive atom" → It's a positively charged ION
- ✗"Loses electrons" alone is incomplete → State WHY (to achieve stable configuration)
- ✗Configuration errors: Li⁺ is NOT "2,1" → It's "2" (electron is LOST)
- ✓Always relate charge to proton/electron imbalance: "11 protons, 10 electrons = +1"
Section A: Definitions & Concepts (5 Questions)
Define the term cation.
Define the term anion.
State what is meant by the term ion.
Explain why noble gases do not form ions.
State the charge on a metal ion and explain why metals form this type of ion.
Section B: Electronic Configurations (5 Questions)
Write the electronic configuration of a lithium ion (Li⁺).
Write the electronic configuration of a fluoride ion (F⁻).
Write the electronic configuration of an oxide ion (O²⁻).
A magnesium ion has the electronic configuration 2,8. State the charge on this ion and explain your answer.
An aluminium ion (Al³⁺) has the same electronic configuration as a neon atom. Write this electronic configuration.
Section C: Explaining Ionic Charge (5 Questions)
Explain why a sodium ion has a charge of +1.
Explain why a chloride ion has a charge of -1.
A sulfur atom has 16 protons. Predict the charge on a sulfide ion and explain your answer.
Calcium forms ions with a +2 charge. Explain this in terms of electron transfer and proton/electron numbers.
Two ions, X²⁺ and Y⁻, both have the electronic configuration 2,8. Deduce the identities of elements X and Y, showing your reasoning.
🎯Key Success Criteria
For Definitions:
- • Use precise terminology ("ion", not "particle")
- • Specify charge type (positive/negative)
- • Mention electron loss/gain where relevant
For Configurations:
- • Count electrons AFTER loss/gain
- • Remember: Cations have FEWER electrons
- • Anions have MORE electrons
For Charge Explanations:
- • State original proton/electron count
- • Explain electron transfer
- • Calculate final proton-electron difference
Mark Scheme Keywords:
- • "Stable configuration"
- • "Full outer shell"
- • "More protons than electrons"
- • "Loses/gains electrons"
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