Chapter 3: The Atom (Part 1)

What is an atom?

An atom is the basic building block of matter. It is made up up protons, neutrons and electrons.

What is a protons charge and where is it found?

(+) charge

Found in the nucleus

Describe the Cathode Ray Tube.

At one end of a glass tube, there is a cathode (negative electrode) and at the other an anode (a positive electrode). When a high voltage as applied, a beam called a cathode ray appeared. When a positive plate was placed above the tube, the ray was attracted upwards towards the plate, indicating that the rays charge was negative

Describe the gold foil experiment.

Conducted by Rutherford, a beam of alpha particles was shot into a very thin sheet of gold foil . Some of the rays were deflected, and some went through. This concluded that the atom was mainly empty space, and that electrons are outside the nucleus.

Name the 5 postulates

1.) elements are made up of tiny particles called atoms

2.) atoms of different elementS have different masses and properties

3. Atoms combine in simple, whole number ratios.

4. Matter cannot be subdivided, created, or destroyed.

5. All atoms of a given element are identical in mass and properties

What two forces are at work in the nucleus?

Electromatic force - acts b/w charges; tries to pullelectrons to nucleus

Strong nuclear force - holds protons and neutrons together