Pulling electrons off, step by step

Science · Chemistry · ages 16-17

Name ______________________ Date ____________

Successive values suddenly leap when...
- The temperature rises
- Atoms join into molecules
- A closer shell is next
First ionisation energy is the energy to...
- Add an electron to a gaseous atom
- Take one electron off gas atoms
- Split a nucleus apart
Ionisation energy generally rises across a period.
Circle one: True False
Why does aluminium ionise more easily than magnesium?
- It holds fewer protons
- A higher 3p electron
- It starts a new period
An element shows three easy ionisations, then a leap. Which group fits?
- Group 5
- Group 1
- Group 3
Why does sulfur dip below phosphorus?
- Sulfur holds fewer shells
- Paired electrons repel
- Phosphorus is a metal
A student says the dip at sulfur proves a new shell starts. What is wrong?
- A dip is pairing, not a shell
- Dips never happen in a period
- Sulfur has no p electrons
An unknown element has successive values 590, 1150 and 4900 kJ per mol. Which group fits best?
- Group 1
- Group 2
- Group 3

Answer key

For grown-ups. Fold this page away before handing over the rest.

A closer shell is next · Closer shells grip far tighter, so the cost jumps.
Take one electron off gas atoms · One electron leaves each lone gaseous atom.
True · A growing nuclear charge grips the same shell harder.
A higher 3p electron · The 3p electron sits higher and further out than the 3s pair.
Group 3 · Three outer electrons means group 3.
Paired electrons repel · Sharing an orbital adds repulsion that helps one partner leave.
A dip is pairing, not a shell · Small dips reveal sub-shell detail, not new shells.
Group 2 · Two cheap removals then a leap means two outer electrons.