Nuclear physics

What you'll learn

1. 1

   Imagine an atom is like a tiny solar system. The nucleus is the sun at the centre, made of protons and neutrons stuck together.

2. 2

   What two particles are found in the nucleus?

3. 3

   Here's a diagram of a helium nucleus — 2 protons and 2 neutrons huddled together.

4. 4

   Let's calculate the number of neutrons in a carbon-12 atom. Carbon has 6 protons.

5. 5

   Build a uranium-238 nucleus. Uranium has 92 protons. How many neutrons?

6. 6

   How many neutrons in uranium-238? (atomic number = 92)

7. 7

   When the nucleus is unstable, it can decay — shooting out particles or energy. That's radioactivity!