Midnight Halloween movie showing on October 24th at

Broadway Cinemas

• Paranormal Activity or Witch Hunt- I • 8 dollars per ticket• Proceeds go to Project Graduation• You may purchase these tickets in the office!• Tickets are limited

The Atomic Theory

The Atom

Protons and Neutrons

Atom

An atom is the smallest particle into which an element can be divided and still be the same substance.

Atomic Theory

The existence of atoms is not a new idea. Atomic theory has been around for more than 2,000 years. A theory is a unifying explanation for a broad range of hypotheses and observations that have been supported by testing.

Atomic Theory

The Atomic Theory grew as a series of models that developed from experimental evidence. As more evidence was collected, the theory and models were revised.

John Dalton All substances are made of atoms. Atoms are small particles that

cannot be created, divided, or destroyed. Atoms of the same element are exactly alike, and atoms of different

elements are different. Atoms join with other atoms to make new substances.

J.J. Thomson

Thomson discovered that there are small particles inside the atom. Therefore, atoms can be divided into even smaller parts.

JJ Thomson is credited with discovering “ELECTRONS”

Ernest Rutherford

Rutherford proposed that in the center of the atom is a tiny, extremely dense, positively charged region called the “NUCLEUS”.

Niels Bohr Bohr suggested that electrons traveled around the nucleus

in definite paths. He proposed that no paths are located between the levels, but electrons can jump from a path in one level to a path in another level. (A very good example of this would be a “ladder”.)

Cloud Theory

In the 1920’s scientist determined that electrons do not orbit the nucleus like planets, as Bohr suggested. Instead, electrons move rapidly within a cloudlike region around the nucleus.

James Chadwick

The Neutron, one of the particles in the “Nucleus” of an Atom, is discovered by British physicist James Chadwick.

The Modern Theory

According to the current theory, electrons do not travel in definite paths as Bohr suggested. In fact their paths can not be predicted. Regions inside the atom where electrons are likely to be found are called “ELECTRON CLOUDS”.

Rutherford’s Model

Bohr’s Model

The Modern Theory