2.1 and 2.2 Savvas Chemistry Exploring Atomic Theory and Models

Which scientist is credited with the discovery of the electron?

• John Dalton

• J.J. Thomson

• Ernest Rutherford

• Niels Bohr

What did Rutherford's gold foil experiment demonstrate about the structure of the atom?

• Atoms are indivisible particles.

• Electrons are embedded in a positive sphere.

• Atoms have a small, dense, positively charged nucleus.

• Electrons orbit the nucleus in fixed paths.

Which subatomic particles are found in the nucleus of an atom?

• Electrons and protons

• Neutrons and electrons

• Protons and neutrons

• Protons, neutrons, and electrons

How do isotopes of the same element differ from each other?

• They have different numbers of protons.

• They have different numbers of electrons.

• They have different numbers of neutrons.

• They have different atomic numbers.

Calculate the atomic mass of an element with two isotopes: one with a mass of 10 amu and 20% abundance, and another with a mass of 11 amu and 80% abundance.

• 10.2 amu

• 10.8 amu

• 11.0 amu

• 10.5 amu

Which model of the atom explains the unique atomic emission spectra of elements?

• Dalton's model

• Thomson's model

• Rutherford's model

• Bohr's model

In the Bohr model, what happens when an electron moves from a higher energy level to a lower energy level?

• The atom absorbs energy.

• The atom emits energy.

• The atom becomes ionized.

• The atom becomes unstable.

Which of the following best describes the atomic emission spectrum of an element?

• A continuous spectrum of colors

• A series of bright lines on a dark background

• A series of dark lines on a bright background

• A single color of light

What is the primary difference between atoms of different elements?

• Number of neutrons

• Number of protons

• Number of electrons

• Atomic mass