5.1 Development of Atomic Models

Experiments with cathode rays led to the discovery of the

• proton

• nucleus

• neutrons

• electrons

Who explained the behavior of positively charged particles being deflected from a metal foil as the nucleus?

• Ernest Rutherford

• John Dalton

• Niels Bohr

• Joseph John Thomson

The gold foil experiment led to the discovery of the

• proton

• nucleus

• neutrons

• electrons

In the gold foil experiment, most of the particles fired at the foil

• bounced back

• passed through the foil

• were absorbed by the foil

• combined with the foil

What did Ernest Rutherford conclude about the structure of the atom?

• An atom is indivisible

• Negatively charged electrons are scattered in an atom

• An atom carries a positive charge

• Atom contains a small, dense, positively charged central region

Answer explanation

What did Joseph John Thomson conclude about the structure of the atom?

• An atom is indivisible

• Negatively charged electrons are scattered in an atom

• An atom carries a positive charge

• Atom contains a small, dense, positively charged central region

Answer explanation

A subatomic particle that has about the same mass as a proton,but with no electrical charge is called __________.

• nucleus

• electron

• neutron

• isotope

Answer explanation

Bohr’s theory helped explain why __________.

• electrons have negative charge

• most of the mass of the atom is in the nucleus

• excited hydrogen gas gives off certain colors of light

• atoms combine to form molecules

Answer explanation

Most of the volume of an atom is occupied by the __________.

• nucleus

• electron cloud

• neutron

• proton

Answer explanation

Who explained the nature of matter being made up of indivisible particle, called atomos?

• Democritus

• John Dalton

• Aristotle

• Joseph John Thomson