Introduction to Atomic Particles

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

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

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

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

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

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

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

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

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

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

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

Time to practice on your own!