Structures

• The nucleus of an atom is made of protons & neutrons
• The shell of an atom has electrons, the central one having only 2 and the outer shells being made up of 8 (full)
• Protons have a positive charge
• A neutron is uncharged
• Electrons have a negative charge
• A solid to get to a liquid melts and to get back into a solid it freezes or solidifies
• A liquid to get to a gas evaporates or boils and to get back to a liquid it must condense