1. The Structure of an Atom
Physical Science
The Structure of an Atom

2. The Structure of an Atom
Properties of Subatomic Particles
Protons – positively charged particle in the nucleus.
Electrons – negatively charged particle in the space outside the nucleus
Neutrons – neutral particle in the nucleus.

3. Comparing Subatomic Particles

4. Atomic Number and Mass Number
Atomic Number – atoms of any given element have the same number of protons. The atomic number tells you the number of protons. The number of proton defines the atom and is not variable.
(the number of protons = the number of electrons for neutral atoms)
Mass Number – the sum of the protons and the neutrons.

5. Isotopes
Isotopes are atoms of an element with different numbers of neutrons, which gives them different mass numbers.
With most elements, it is hard to notice physical or chemical differences in isotopes.
Isotopes are written with the mass number to indicate WHICH isotope. For example, carbon-14 or oxygen-17

6. Homework
P. 112 #1-9
P. 118 #1-8