Unit 3 Post Assessment Remediation (PAR)

Which statement describes the earliest model of the atom?

• An atom is an indivisible hard sphere.

• An atom has a small, dense nucleus.

• Electrons are negative particles in an atom.

• Electrons in an atom have wave-like properties.

The discovery of the electron as a subatomic particle was a result of

• the beryllium foil experiment

• ancient Greek philosophy

• the gold foil experiment

• experiments with cathode ray tubes

The results of the gold foil experiment led to the conclusion that an atom is

• mostly empty space and has a small, negatively charged nucleus

• mostly empty space and has a small, positively charged nucleus

• a hard sphere and has a large, negatively charged nucleus

• a hard sphere and has large a large, positively charged nucleus

Tags

NGSS.HS-PS1-8

In the wave-mechanical model of an atom, an orbital is defined as

• a region of the most probable neutron location

• a region of the most probable electron location

• the straight-line path of a neutron

• the straight-line path of an electron

Given a list of atomic model descriptions: A: electron shells outside a central nucleus B: hard, indivisible sphere C: mostly empty space Which list of atomic model descriptions represents the order of historical development from the earliest to most recent?

• A, B, C

• A, C, B

• B, C, A

• B, A, C

Which element is listed with the number of protons in each of its atoms?

• nitrogen, 14

• silicon, 14

• oxygen, 16

• phosphorus, 16

Which statement describes two different isotopes of carbon?

• The isotopes contain the same number of neutrons and have the same atomic number

• The isotopes contain the same number of neutrons but have a different atomic number

• The isotopes contain a different number of neutrons but have the same atomic number

• The isotopes contain a different number of neutrons and have a different atomic number

A potassium atom has a mass number of 37. What is the number of neutrons in this atom?

• 15

• 18

• 22

• 37

The table below gives the atomic mass and the abundance of the two naturally occurring isotopes of copper. Which numerical setup can be used to calculate the atomic mass of the element copper?

• (62.93 u)(30.85) + (64.93 u)(69.15)

• (62.93 u)(69.15) + (64.93 u)(30.85)

• (62.93 u)(0.3085) + (64.93 u)(0.6915)

• (62.93 u)(0.6915) + (64.93 u)(0.3085)

What is the net charge of a monatomic ion that has 15 protons, 16 neutrons, and 18 electrons?

• 2 +

• 2 –

• 3 +

• 3 –