S4.6.1 For the adult
Inside the atom
An atom is too small to see. How do we know what is inside it?
What this chapter teaches
An atom has a tiny nucleus of protons and neutrons, with electrons outside it. The number of protons is the atomic number and decides the element. Protons plus neutrons make the mass number.
Three questions to ask
There is no one right wording. Listen for the idea.
- What is the charge of a proton, a neutron and an electron?
- An atom has atomic number 8 and mass number 16. How many neutrons does it have?
- Why is a whole atom neutral?
After the chapter, the learner can
- Give the charge, mass and place of protons, neutrons and electrons
- Work out the number of each particle from atomic and mass numbers
What they copy into their notebook
An atom has a tiny nucleus of protons (+1) and neutrons (0). Electrons (−1) move outside. Atomic number = protons. Mass number = protons + neutrons. A neutral atom has equal protons and electrons.