The periodic table
3 marks · EasyThe table below shows information for three elements:
| Element | Symbol | Atomic number | Mass number |
|---|---|---|---|
| Boron | B | 5 | 11 |
| Silicon | Si | 14 | 28 |
| Argon | Ar | 18 | 40 |
Complete the following table by giving the number of protons, neutrons and electrons for each atom.
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.
Show answer
Must show: Protons: 5,14,18; Neutrons: 6,14,22; Electrons: 5,14,18
Common mistakes: Adding atomic and mass number for neutrons; Mismatching protons and electrons
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Boron row correct: protons 5, neutrons 6, electrons 5.
B2 · 1 mark · Silicon row correct: protons 14, neutrons 14, electrons 14.
B3 · 1 mark · Argon row correct: protons 18, neutrons 22, electrons 18.
Worked solution
| Element | Protons | Neutrons | Electrons |
|---|---|---|---|
| Boron | 5 | 6 | 5 |
| Silicon | 14 | 14 | 14 |
| Argon | 18 | 22 | 18 |