Atomic structure and the periodic table
Learn Atomic structure and the periodic table for Year 9 pupils (ages 13–14). Free practice questions, lessons and worked examples — aligned to the UK National Curriculum.
What you'll learn
- 1
An atom has a tiny central nucleus of protons and neutrons, with electrons in shells around it.
- 2
The atomic number is the number of protons — it decides which element it is. Change the protons and you have a different element entirely.
- 3
What decides which element an atom is?
- 4
Common error: picturing the atom as solid. It is overwhelmingly empty space — if the nucleus were a pea in the middle of a football pitch, the electrons would be at the stands.
- 5
What did most particles do in the gold foil experiment?
- 6
Apply it: sodium has atomic number 11 and mass number 23. So 11 protons, 11 electrons, and 23 − 11 = 12 neutrons.
- 7
An atom has atomic number 17 and mass number 35. How many neutrons?
Practise Atomic structure and the periodic table with Whizlo
Free AI-tutored lessons, unlimited practice questions, and progress tracking for ages 13–14. Aligned to the UK National Curriculum.