1. Atomic Structure Notes
7-5.1, 7-5.2, 7-5.3, 7-5.4, 7-5.5

2. The study of ways in which matter interacts, combines, and changes.
What is chemistry?
The study of ways in which matter interacts, combines, and changes.

3. So what is matter?
Matter is composed of extremely small particles, too small to be seen with a microscope, called atoms.
An atom is the smallest part of an element that has the chemical properties of that element.
An atom has mass and takes up space.
An atom is made up of protons (positive), neutrons (neutral), and electrons (negative)

4. Atomic Structure
Atoms are made up of protons, neutrons, and electrons.
The number of protons = the atomic number.
The number of electrons = the atomic number.
The number of neutrons = atomic mass - # of protons

5. How to Read the Periodic Table
Round it, and that
number is equal to the
# of protons and # of
neutrons

6. Find the number of protons, neutrons, and electrons
Boron:
Atomic mass = 10.81
Atomic number = 5
Step 1) Round the atomic mass to the nearest whole number: 11.
Step 2) Protons = the atomic number: 5.
Step 3) Electrons = the atomic number: 5.
Step 4) Neutrons = atomic mass – protons = 11 – 5= 6.

7. Drawing a model of an atom
The nucleus is made up of the protons and neutrons.
The electrons float around the outside of the nucleus in groups, or shells. The first shell has 2 electrons. When that fills up, they fill up the 2nd shell which can hold 8. When that fills up, the 3rd shell holds 18.

8. What is an atom? Draw and Label this.
Nucleus = Protons and Neutrons
Protons = Positive Charge
Neutrons = Neutral
Electrons = Negative Charge
Nucleus