Atoms

Atoms

1. It's in the middle of the atom.

   • It contains protons and neutrons.
     • It has a positive charge because of the protons.
       • Almost the whole mass of the atom is concentrated in the nucleus.

2. Move around the nucleus in electron shells.

   • They're negatively charged.
     • They are small but cover a lot of space.
       • The volume of their orbit determines the size of the atom.
         • Electrons have virtually no mass.

3. Protons are heavy and positively charged.

   • Neutrons are heavy and neutral.
     • Electrons are tiny and negatively charged.

4. Number of protons equal the number of electrons.

   • Neutral atoms have no charge overall.
     • This is because they have the same number of protons and electrons.
       • The charge on the electrons is the same size as the charge on the protons but opposite so the charges cancel out.

5. The Atomic number (Bottom number) is the same as the number of protons.

   • Atoms of the same elemetns all have the same number of protons
     • So atoms of different elements will have different numbers of protons.
       • To get the number of neutrons, subtract the atomic number from the mass number

6. The mass number (Top number) is the total number of protons and neutrons

   • The mass number is always the biggest number.
     • On a periodic table the mass number is the relative atomic mass.