Physical Science
T2
Atomic Theory (portfolio)

Current Atomic Theory
• According to the modern atomic theory, most of an atom is empty space. An atom consists of a small, dense nucleus surrounded by electrons. Atoms contain three types of subatomic particles: protons, neutrons and electrons. The nucleus contains only protons and neutrons.
• Protons are particles with a positive charge.
• Neutrons are particles with a neutral, or no, charge.
• Electrons are particles that orbit around the nucleus in regions with different levels of energy. Electrons are much smaller in size and mass than protons and neutrons and have a negative charge.
Electrons are found in specific energy levels within the electron cloud. • The protons in the nucleus of an atom are all positively charged, so they repel each other.
The force of repulsion is counteracted by a stronger force, the strong nuclear force. The strong nuclear force holds the protons in a nucleus close together. In fact, the strong nuclear force is the strongest force that we know of.

Democritus
• Greek Philosopher
• One of the first people to suggest that the world is made up of tiny objects called atoms

Dalton (1800’s)
• Built upon Democritus ideas
• 5 main ideas:
– All matter is made of atoms.
– Atoms cannot be made or destroyed.
– All atoms of a given element are identical in mass and properties.
– Compounds are formed by a combination of two or more different kinds of atoms.
– A chemical reaction occurs when atoms are rearranged. Thomson
• Won Nobel Peace Prize in 1906
• Main ideas
– Atoms contain negatively charged particles called electrons • Atoms are made up of smaller parts

– Matter was electrically neutral
– Positively charged matter
– “Plum Pudding” model

Rutherford
• Thomson’s research student
• Gold Foil experiment – disproved Thomson’s theory – Electrons orbit the nucleus

Bohr
• Studied under Thomson and Rutherford
• Electron energy/levels
• Electron shells (bonding)

• Won Nobel Peace Prize in 1922

Schrodinger (1930)
• Electrons are too small and too fast to describe exactly where they are located.

Chadwick
• And we have…neutrons!

Atomic
Theory
Portfolio

Directions:
Research and respond to the following:
Were there experiences in his life that led to his interest in science and the study of the atom? Defend his work on the atom and its contribution to the modern atomic model. Point out which contributions are present in the modern atomic model and which were eventually disproven and thus are not part

Reminders:

*Reliable Sources
(cite your sources)
* Put information into your own words! * Use TII for this assessment. No TII originality report=
NO CREDIT

CHOICES:
 Democritus
 Dalton
 Thomson
 Rutherford
 Bohr
 Schrodinger
 Chadwick

Ernest
Rutherford

.

Were there experiences in his life that led to his interest in science and the study of the atom?
O Ernest received his first science book when he was 10.

Out of all the many experiments in the book one, on using the speed of sound to determine the distance to a firing cannon, gave him the knowledge to surprise his family by estimating the distance to a lighting flash.
*I think it was also this book that