1. Q: What’s an atom?
The smallest piece of matter that still has all the properties and characteristics of that type of matter
EX. An atom of gold still has the same chemical and physical properties as a chunk of gold

2. Q: What’s an atom? Brownian Motion
Perpetual movement of particles (atoms jiggling/vibrating)
Named after Robert Brown (Scottish botanist).

3. Q: What does an atom look like?
An atom is mostly empty space
Atoms have a small, dense nucleus at their center
Atoms contain what we call subatomic particles (3 subatomic particles)

4. Q: What does an atom look like? (3 subatomic particles)
Electron (symbol e-)
Location- electron cloud (outside nucleus)
Charge- negative (each electron has a -1 charge)
Relative mass- 1/1840
1/1840 the size of the other particles = SMALL

5. Q: What does an atom look like? (3 subatomic particles)
Proton (symbol p+)
Location- nucleus
Charge- positive (each proton has a +1 charge)
Relative mass- 1

6. Q: What does an atom look like? (3 subatomic particles)
Nucleus (symbol n0)
Location- nucleus
Charge- neutral (each neutron has zero charge, not charged at all!)
Relative mass- 1

7. Draw a picture of an atom below
Draw a picture of an atom below. Label each of the three subatomic particles, as well as the nucleus and electron cloud.

8. Q: What is the overall charge of the nucleus in an atom? Why?
Nucleus is made of protons and neutrons (p+ and n0)
Since the only charged particles are protons and they have a positive charge, the overall charge is positive

9. Announcements
We will take the first half of your exam after the next unit (Unit 4)
Parent Teacher Conferences
Tonight (5 – 8 pm)
Next week Wednesday (10/19, 3 – 6 pm)
Next week Wednesday
Freshmen will take the social studies MEAP
During 1st hour
You MUST bring your ID!