Unit 2 Review Questions

Which scientist is credited with discovering the electron and proposing the 'plum pudding' model of the atom?

• Ernest Rutherford

• Niels Bohr

• J.J. Thomson

• Erwin Schrödinger

The gold foil experiment, which led to the discovery of the atomic nucleus, was conducted by which scientist?

• J.J. Thomson

• Niels Bohr

• Erwin Schrödinger

• Ernest Rutherford

Which of the following scientists proposed a model of the atom where electrons orbit the nucleus in specific, quantized energy levels, similar to planets orbiting the sun?

• J.J. Thomson

• Ernest Rutherford

• Erwin Schrödinger

• Niels Bohr

The quantum mechanical model of the atom, which describes electrons in terms of wave functions and probability clouds, was developed by which physicist?

• Erwin Schrödinger

• Niels Bohr

• Ernest Rutherford

• J.J. Thomson

How is the mass number of an atom calculated?

• Number of protons minus the number of electrons

• Number of protons plus the number of electrons

• Number of neutrons minus the number of protons

• • Number of protons plus the number of neutrons

An atom has 15 protons, 16 neutrons, and 15 electrons. What is its mass number?

• 15

• 16

• 30

• 31

Tags

NGSS.MS-PS1-1

Which of the following is true about two different isotopes of the same element?

• They have the same mass number.

• They have a different atomic number.

• They have the same number of neutrons.

• They have the same number of protons.

How is the hyphen notation for an isotope written?

• Element-Mass Number

• Element-Atomic Number

• Mass Number-Element

• Atomic Number-Element

Copper has two stable isotopes: copper-63 with a mass of 62.93 amu and copper-65 with a mass of 64.93 amu. If the average atomic mass of copper is 63.55 amu, which isotope is more abundant?

• Copper-63

• Copper-65

• They have equal abundance.

• It is impossible to determine with the information given.

Tags

NGSS.HS-PS1-8

An element has two isotopes. Isotope A has a mass of 20.0 amu and a natural abundance of 75%. Isotope B has a mass of 22.0 amu and a natural abundance of 25%. What is the average atomic mass of this element?

• 20.25 amu

• 20.50 amu

• 21.00 amu

• 21.50 amu