Atoms and Molecules

What is the smallest particle of an element that retains its chemical properties?

• molecule

• ion

• atom

• compound

What are the three subatomic particles that make up an atom?

• protons, neutrons, and positrons

• protons, electrons, and photons

• protons, neutrons, and quarks

• protons, neutrons, and electrons

Which subatomic particle has a positive charge?

• neutron

• electron

• proton

• photon

Which subatomic particle has a negative charge?

• electron

• neutron

• proton

• positron

Which subatomic particle has no charge?

• photon

• neutron

• electron

• proton

What is the atomic number of an element?

• The atomic number of an element is the number of protons in the nucleus of an atom.

• The atomic number of an element is the number of protons and neutrons in the nucleus of an atom.

• The atomic number of an element is the number of electrons in the nucleus of an atom.

• The atomic number of an element is the number of neutrons in the nucleus of an atom.

What is the mass number of an element?

• Total number of electrons in the nucleus

• Total number of protons in the nucleus

• Total number of neutrons in the nucleus

• Total number of protons and neutrons in the nucleus

What is the difference between atomic number and mass number?

• The atomic number is the number of electrons in the nucleus, while the mass number is the total number of protons and neutrons in the nucleus.

• The atomic number is the number of protons and neutrons in the nucleus, while the mass number is the total number of protons in the nucleus.

• The atomic number is the number of protons in the nucleus, while the mass number is the total number of protons and neutrons in the nucleus.

• The atomic number is the number of neutrons in the nucleus, while the mass number is the total number of protons and electrons in the nucleus.

What is an isotope?

• A variant of an element with the same number of electrons but a different number of protons.

• A variant of an element with the same number of neutrons but a different number of protons.

• A variant of an element with the same number of protons but a different number of neutrons.

• A variant of an element with the same number of protons but a different number of electrons.

What are valence electrons?

• Electrons in the innermost energy level of an atom.

• Electrons in the outermost energy level of an atom.

• Electrons in the nucleus of an atom.

• Electrons in the middle energy level of an atom.