Atom Structure - Defining the Atom

Multiple Choice

Why is it important to understand what an atom is in the study of chemistry?

• Because atoms are the building blocks of matter and understanding them helps explain the properties and behaviors of elements.

• Because atoms are only found in living things.

• Because atoms are the largest particles in the universe.

• Because atoms are not important in chemistry.

Multiple Choice

Who was the physicist that first noticed radiation in cathode tubes?

• Sir William Crookes

• J.J. Thomson

• Robert Millikan

• Ernest Rutherford

Multiple Select

Which of the following conclusions can be drawn from the cathode ray experiments shown in the diagram?

• Particles in the ray are charged

• Particles in the ray have a negative charge

• Particles in the ray are neutral

• Particles in the ray have a positive charge

Multiple Choice

What was the first subatomic particle to be discovered?

• Electron

• Proton

• Neutron

• Photon

Multiple Choice

What was the main purpose of changing the electric field in the oil drop experiment?

• To control the speed at which oil drops fell

• To increase the number of oil drops

• To heat the oil drops

• To remove all electrons from the oil drops

Multiple Choice

According to the plum pudding model proposed by J.J. Thomson, how are electrons arranged in the atom?

• Embedded throughout a sphere of positive charge

• Orbiting around a dense nucleus

• Clustered at the center of the atom

• Arranged in fixed shells

Multiple Select

Which of the following statements describe Rutherford's hypothesis before his gold foil experiment?

• Atoms have no strong positive charge

• Alpha particles would pass through atoms with little deflection

• Atoms have a dense central nucleus

• Electrons are evenly distributed in a sphere of positive charge

Multiple Choice

Which observation from the gold foil experiment led Rutherford to propose the existence of a dense, positively charged nucleus in the atom?

• Most alpha particles passed through the foil with little or no deflection.

• Alpha particles were absorbed by the gold foil.

• All alpha particles were deflected at large angles.

• Alpha particles bounced back from the zinc-sulfide screen.

Multiple Select

Which of the following statements about the nucleus is/are correct?

• It contains all the positive charge of the atom.

• It is located at the center of the atom.

• It contains electrons.

• It contains most of the atom's mass.

Multiple Choice

What is the smallest particle of an element that retains the properties of the element called?

• Atom

• Molecule

• Proton

• Electron