1. Properties of Subatomic Particles

2. Subatomic Particles • Proton • Positively charged particle • Equal to the Atomic Number • Electron • Negatively charged particle • Equal to # of protons (in a neutral atom) • Neutron • Uncharged particle (neutral) • Equal to Mass Number – Atomic Number

3. Location of Subatomic Particles • Protons and neutrons are found in the nucleus • Electrons located in energy levels (orbitals) outside of the nucleus

4. Atomic Number 6 C Chemical Symbol Element Name Carbon Atomic Mass/Weight 12.011

5. Atomic Number • Number of protons in atom • Number of electrons in atom • Mass Number (Atomic Mass rounded) • Number of protons plus neutrons • Chemical Symbol • One or two letters that stand for the element

6. 126C protons=6 electrons = 6 neutrons=6 (12-6) atomic number mass number (rounded atomic mass)

7. Ions -atoms that have gained or lost electrons (negative particles) Anion: atoms that have gained electrons and have a negative charge Cation: atoms that have lost electrons and have a positive charge

8. Isotopes -Atoms that have the same number of protons, but different numbers of neutrons -different mass numbers Neon-20 10 neutrons Neon-21 11 neutrons Neon-22 12 neutrons

9. (Average) Atomic Mass -isotopes occur in nature in a certain percentage (percent natural abundance) -the atomic mass of an element is a weighted average mass of atoms occurring in nature -see table 4.3

10. (.9889 * 12.000) + (0.0111 * 13.003) = 12.011