Three parts to an atom

The nucleus is where to find almost all of the mass of an atom

Protons and neutrons sit together like apples and oranges in a bowl to form the nucleus

Electrons fly around the nucleus in orbit, like fruit flies hovering around rotting fruit

Proton

•  Protons are positively charged
• The number of protons in an atom tells you the atomic number of the atom 
• An element (like Carbon) can never change the number of protons in it

Because protons are all positively charged, they don't want to be near each other! In fact, if there aren't enough neutrons in a nucleus, the atom decays!

Neutron

• Neutrons have no charge (not + or - )
• You can find the number of neutrons in an element by subtracting the atomic number from the atomic mass 
• If we change the number of neutrons in an atom, we say that new atom is an isotope (more on that later!).

A curious force that neutrons use to hold the nucleus together is called the strong force. It is the energy from this strong force that is released in nuclear weapons.​

Electron

• Electrons are negatively charged
• The number of electrons in an atom is the same as the number of protons, UNLESS it's an ion (more on ions later) 
• Electrons only live in certain orbitals 
• Electrons in the outer orbitals determine what the atom will bond with, react with, and behave (they're very important!)

Metals are very good at sharing! They readily lose their electrons, and electrons end up flowing from one atom to the next, to the next, to the next. We call this, electricity! ​