Atomic Theory

What major contribution did Rutherford provided to the Atomic Theory?

Discovered that atoms have a positive charge in the core and negative charges outside the core.

Atoms are mostly made of space.

Who conducted the gold foil experiment?

Ernest Rutherford

What major contribution did Thomson make to the Atomic Theory?

Discovered that atoms can be split into smaller particles (protons and electrons).

Who made the plum pudding model of an atom?

J.J Thomson

What does the plum pudding model show?

An atom is a ball of positively charged material with negatively charged particles floating around inside.

What did Lavoiser contribute toward the Atomic Theory?

Proposed the Law of Conservation of Matter

Created the metric system

What does the Law of Conservation of Matter State?

Matter cannot be created or destroyed. It can only be converted into other matter.

What was Dalton's contribution to the Atomic Theory?

Atoms of the same element are exactly alike.

Atoms of different elements are different.

Atoms can join with other atoms to make new substances.

What was Bohr's contribution to the Atomic Theory?

Electrons travel around the nucleus of an atom in definite paths.

Electrons can jump from one energy level (path) to another.

What was Schrodinger's contribution to the Atomic Theory?

The exact location of an electron cannot be found.

Electrons travel in electron clouds which represent where the electron is most likely to be found.

What was Chadwick's contribution to the Atomic Theory?

Discovered the existence of neutrons.

He found that the atomic mass of most elements is double the number of protons for one atom of that element.

What does the Bohr model look like?

Similar to a model of the solar system.

The nucleus (with protons) is in the center.

Electrons orbit the nucleus in different levels.

How many electrons can travel in each orbit (level) of an atom?

First level (K) = 2

Second level (L) = 8

Third level (M) = 8

Fourth level (N) = 18

Fifth level (O) = 18

Sixth level (P) = 32

Seventh level (Q) = 32

What is the Atomic Number equal to?

The number of Protons

How do you calculate the number of Neutrons?

Atomic Mass - Atomic Number = # of Neutrons

How do you determine the number of electrons in an uncharged atom?

Protons = Electrons

What was done in the gold foil experiment?

A beam of positively charged particles was aimed at a piece of gold foil.

Most of the light passed through the foil in a straight line.

Many particles bounced off the foil in different directions.

What are protons?

Positively charged particles

What are electrons?

Negatively charged particles

What are neutrons?

Neutral charged particles

Where are the protons and neutrons located in an atom?

The nucleus