1. Introduction to Atomic Particles

2. How will I know if I am successful? – I can name and describe three types of atomic particles Charge Location Mass – I can find the atomic number and mass number, and can explain what they represent – I can calculate the number of neutrons in an atom

3. What are atoms? An atom a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons The atom is made up of three different types of particles called. Subatomic particles

4. Protons charged Located in the Each proton has a (atomic mass unit) positively nucleus Mass of 1 amu

5. Neutrons particles Located in the Each neutron has a neutral nucleus Mass of 1 amu

6. Electrons charged Move rapidly in space (in orbits) Have almost negatively Around the nucleus No mass

7. Model of the Atom The physicist Nils Bohr developed a model of the atom that looked like the picture below. Part of AtomCount protons neutrons electrons nucleus total total charge 11 12 11 23 0

8. Parts of the Atom Part of Atom Overall Charge Atomic Weight (amu) Description (where found?) nucleus 0 (neutral) depends on atom proton neutron electron Part of the Nucleus +1 (positive) 0 (neutral) -1 (negative) 1 1 Almost 0 Centre of the Atom In Nucleus Around Nucleus

9. is an internationally recognized system that allows anyone to communicate information about the atom Standard Atomic Notation

10. Note- In the periodic table, notation looks like this:

11. Atomic Number - Number of (also equal to the number of electrons in a neutral atom) - Determines the identity of the atom Mass Number - the sum of the and in an atom - mass number = atomic number + number of neutrons protons neutrons

12. Calculating Neutrons Number of neutrons = Mass Number (protons + neutrons) – Atomic Number (protons) E.g. Protons: Neutrons: Electrons: 2 2 2

13. Time to practice on your own!