What is the atomic number of an element?

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

• The atomic number is the mass of an atom in atomic mass units.

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

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

What does atomic mass represent in an atom?

• Atomic mass is the total number of protons in an atom.

• Atomic mass is the mass of a single proton in an atom.

• Atomic mass indicates the number of electrons in an atom.

• Atomic mass represents the average mass of an atom's isotopes.

Which of the following is an example of an isotope?

• Hydrogen-1

• Oxygen-16

• Nitrogen-14

• Carbon-14

Which of the following pairs are isobars?

• Hydrogen-1 and Helium-4

• Boron-10 and Lithium-6

• Carbon-12 and Oxygen-16

• Carbon-14 and Nitrogen-14

What is the main difference between isotopes and isobars?

• Isotopes have the same number of protons but different neutrons; isobars have the same atomic mass but different protons.

• Isotopes are elements with different chemical properties; isobars are the same element.

• Isotopes have the same number of electrons; isobars have different atomic numbers.

• Isotopes have different atomic masses; isobars have the same number of neutrons.

What is the molecular mass of water (H2O)?

• 16.00 g/mol

• 20.18 g/mol

• 22.99 g/mol

• 18.02 g/mol

Which of the following elements has an atomic number of 6?

• Oxygen

• Nitrogen

• Hydrogen

• Carbon

What is the atomic mass of Carbon-12?

• 14 amu

• 10 amu

• 12 amu

• 8 amu

Which of the following statements is true about isotopes?

• Isotopes of an element have different numbers of protons and neutrons.

• Isotopes are atoms of different elements with the same mass number.

• Isotopes of an element have the same number of protons but different numbers of neutrons.

• All isotopes of an element are radioactive.

What is the molecular mass of carbon dioxide (CO2)?

• 32.00 g/mol

• 28.02 g/mol

• 18.02 g/mol

• 44.01 g/mol