Task Description: Today We Did Some Science Experiments
Each element has a different number of protons. This is how we tell them apart. They also have different number of neutrons and electrons, but these can change. Helium has 2 protons so its atomic number is 2, it also has 1 or 2 neutrons and 2 electrons. This is different to Lithium which has 3 protons and an atomic number of 3. It also has 3 electrons and 3 or 4 neutrons. Each element has its own symbol.