Practice question · Match the pairs
Match each species to its size relative to the neutral atom.
- A cation formed by losing the whole outer shell
- An anion formed by adding an electron
- An atom one place further right in the period
- An atom one place further down the group
- Much smaller than the atom
- Larger than the atom
- Considerably larger than the atom
- Slightly smaller than the atom
Hints
- Losing electrons contracts, gaining electrons expands.
- Adding a whole shell changes size far more than adding one proton does.
Show the answer
- A cation formed by losing the whole outer shell → Much smaller than the atom
- An anion formed by adding an electron → Larger than the atom
- An atom one place further right in the period → Slightly smaller than the atom
- An atom one place further down the group → Considerably larger than the atom
Why
Emptying a shell contracts an ion sharply; an extra electron adds repulsion without extra nuclear charge and expands it; one step right shrinks slightly; one step down adds a whole shell and grows a lot.
Practise Periodic Properties
The app has 3 more questions on this lesson, and keeps your place in the course. Chemistry I is free to start.
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