Unit 3 Atoms

What particle always has a mass of one atomic mass unit (amu) and no charge?

• A Neutron

• A Proton

• An Electron

• An Atom

If an atom has two protons and three electrons, then the atom is

• Positively charged

• Negatively charged

• Radioactive

• Neutral

What happens when an atom gains an electron?

• The atom loses a proton.

• The atom attracts additional electrons.

• The atom increases in atomic mass.

• The atom becomes negatively charged.

An atom of beryllium has 4 protons, 4 electrons, and 5 neutrons. What is its mass number?

• 4

• 5

• 8

• 9

If the solar system were used as a model of an atom, what would the Sun most likely represent?

• An Ion

• A Nucleus

• A Neutron

• An Electron

An atom has a mass of 24 and a nuclear charge of 12. Which statement about the atom is accurate?

• It has twice as many protons as electrons.

• It has twice as many neutrons as protons.

• It has equal numbers of neutrons and protons.

• It has equal numbers of nuclear particles and electrons.

What are the parts that make up an atom?

• electrons, neutrons, and protons

• electrons, protons, and gamma rays

• neutrons, photons, and beta particles

• neutrons, protons, and alpha particles

Pressure

• amount of force applied per unit of area

• states that the volume of a gas increases with increasing temperature, if pressure is constant

• an explanation of how particles in matter behave

• states that pressure of a gas increases if the volume decreases and pressure of a gas decreases if volume increases, when temperature is constant

An atom becomes an ion with a -1 charge because the atom

• gains one electron

• loses one electron

• gains one proton

• loses one proton

Charge of a Neutron

• Negative

• Positive

• No charge

• An ion