ATOMS AND RADIOACTIVITY
4 marks · NormalFigure 1 shows a simplified model of a lithium atom.
State the charge on each of the following sub-atomic particles:
Complete the table for a lithium atom, which has atomic number 3 and mass number 7.
| Particle | Number in atom |
|---|---|
| Proton | |
| Neutron | |
| Electron |
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) — · must show Proton: +1 (positive), Neutron: 0 (neutral), Electron: −1 (negative)
(b) — · must show Proton: 3, Neutron: 4, Electron: 3
Common mistakes: Confusing proton and neutron charges; Wrong electron number
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Marking points
B1 (a) · 1 mark · Correct charge for proton.
B2 (a) · 1 mark · Correct charge for electron AND neutron.
B3 (b) · 1 mark · Correct numbers for protons and electrons.
B4 (b) · 1 mark · Correct number for neutrons.
Worked solution
a) Charges:
| Particle | Charge |
|---|---|
| Proton | +1 |
| Neutron | 0 |
| Electron | −1 |
b)
| Particle | Number in atom |
|---|---|
| Proton | 3 |
| Neutron | 4 |
| Electron | 3 |