Physical Science Unit 3

Early 1900s- Earnest Rutherford

Discovered the Nucleus and came up with the nuclear model.

1932-Chadwick

Discovered the neutron

1920-Heisinberg, de Broglie, Schrodinger

Electrons are waves, wave equation gives us a probability for where an electron is

Why was Daltons theory more successful than Democritus's

because he had evidence to back his theory up

Early 1900s-Niels Bohr

created the Bohr model in which electrons only exist on certain levels

how many electrons are in the first three levels

2, 8, 18

Summarize the main ideas of Dalton's theory

2. Dalton's theory was that all the atoms in one element were identical and, when they merged with atoms from a different element a compound was formed.

How many Valence electrons does nitrogen have

5

Compare and contrast the structure of a atom to a ladder

An atom's structure is similar to a ladder because electrons go up and down energy levels. The ladder couldn't be used as the model because there is no place for the nucleus

Early 1800s-John Dalton

Atomic theory

How did the gold foil experiment lead to the discovery of the nucleus

Because in the experiment the positive charges that passed close to the center were deflected sharply. The charges that were shot directly at the center bounced right back. This meant that there was a positive charge deflecting the particles

Explain how Bohrs model and the modern model of the atom differ in terms of the path of the electron

Because in the model now electrons can not be in between energy levels.

Describe Democritus's atomic theory

Democritus said that the universe was made up of small individual units known as atoms. He said that the movements of atoms made the changes in the matter he was observing happen.

Name 2 features of the modern atom

In the modern atom model there are energy levels and there are valence electrons that fill them

Identify how many electrons can fit in the third level hold and why is this the case

It can hold 18 electrons and this is because there is 1s+3p+5d=9 x 2= 18.

Does the term indivisible describe the atom

No it does not because now we know that an atom can be divided up and split.

What happens when an electron jumps from one energy level to another

The electron goes into an excited state where it absorbs energy known as a photon and then it jumps to another level. It will return to the lower level when it loses the energy thus giving up a photon.

explain what determines how the energy levels are filled

The number of energy levels that are filled in an atom depends on the number of electrons

How did the cathode ray experiment lead to the discovery of electrons

Thomson knew that magnets deflected charges. He argued that because all of the air was removed from the tube the beam must've come from within the atom. The direction in which the deflection went indicated a negative the charge which also meant it came from the cathode.

Compare Thomson and Rutherford's atomic model

Thomson's atomic model and, Rutherford's atomic models are different in many different ways. Thomson's model proposed the idea that cathode rays were made up of negatively charged atoms that came from within the atom. He discovered electrons. While Rutherford proposed the idea that most of the atom's energy was focused on a center called the nucleus.

300 BC-Aristotle

said that matter is earth, fire, water, and aether

300 BC-Democritus

said that matter is made up of tiny particles called atoms