Chapter 7 Understanding the Atom

Multiple Choice

Which scientist believed that matter is made of fire, water, air, and earth?

• Democritus

• John Dalton

• Aristotle

• Isaac Newton

Multiple Choice

Which of the following statements best describes an atom?

• The smallest unit of a chemical element, consisting of protons, neutrons, and electrons.

• A molecule made up of two or more elements.

• A negatively charged particle found outside the nucleus.

• A positively charged particle found inside the nucleus.

Fill in the Blanks

The electron cloud in an atom surrounds the nucleus and contains the

.

Multiple Choice

Which scientific invention allowed scientists to see individual atoms for the first time?

• Electron microscope

• Scanning tunneling microscope (STM)

• Light microscope

• X-ray crystallography

Multiple Select

Which of the following are characteristics of protons?

• Positively charged

• Located inside the nucleus

• Included in the atom’s mass

• May not always be the same number as neutrons

Multiple Choice

Which subatomic particle is negatively charged and located outside the nucleus?

• Electron

• Proton

• Neutron

• Photon

Multiple Choice

According to Thomson's atomic model, what is the arrangement of charges within an atom?

• Positively charged sphere with embedded electrons

• Electrons orbiting a dense nucleus

• Uniform distribution of positive and negative charges

• Electrons and protons in separate layers

Multiple Choice

What observation from Rutherford's gold foil experiment indicated the presence of a dense, positively charged nucleus?

• Some alpha particles bounced back

• All alpha particles passed straight through

• Alpha particles changed color

• Alpha particles lost energy

Fill in the Blanks

Rutherford concluded that most of an atom's mass and positive charge is concentrated in the

of the atom.

Multiple Choice

Which statement best describes the difference between the Bohr atomic model and the modern atomic model?

• The Bohr model describes electrons in fixed circular orbits, while the modern model describes electrons in an electron cloud.

• The Bohr model describes electrons as stationary, while the modern model describes electrons as moving in straight lines.

• The Bohr model describes electrons as part of the nucleus, while the modern model describes electrons as outside the nucleus.

• The Bohr model describes electrons as having no energy, while the modern model describes electrons as having energy.

Fill in the Blanks

Fill in the blank: A proton is made of two

quarks and one down quark.

Multiple Select

Which of the following particles are made up of quarks?

• Protons

• Neutrons

• Electrons

• Photons

Multiple Choice

Which statement best describes isotopes?

• Isotopes are atoms of the same element with different numbers of neutrons.

• Isotopes are atoms of different elements with the same number of neutrons.

• Isotopes are atoms of the same element with the same number of neutrons.

• Isotopes are atoms of different elements with different numbers of neutrons.

Fill in the Blanks

In the late 1800's, scientists discovered that some elements change into other elements

.

Fill in the Blanks

Aristotle believed that matter is made of fire, water, air, and

.