What term describes the mass of an atom relative to other atoms?

What term describes the mass of an atom relative to other atoms?

• A. Relative atomic mass
• B. Atomic number
• C. Isotope
• D. Atomic mass unit

Answer: (D)

Mass is compared using a standard, so the term that describes how heavy an atom is relative to other atoms is the relative atomic mass. This value, written as Ar, tells you how many times heavier (or lighter) an atom is compared to one twelfth of a carbon-12 atom. It’s a dimensionless ratio that comes from comparing the actual masses of the atom’s isotopes and averaging them according to how common they are in nature. The number you see on the periodic table for an element is this relative atomic mass. The atomic mass unit, by contrast, is the unit used to express an actual mass. It’s a way to quantify how heavy something is, but it’s not the description of mass relative to other atoms. Atomic number is just the count of protons, and an isotope is an alternative form of the element with a different number of neutrons.

Mass is compared using a standard, so the term that describes how heavy an atom is relative to other atoms is the relative atomic mass. This value, written as Ar, tells you how many times heavier (or lighter) an atom is compared to one twelfth of a carbon-12 atom. It’s a dimensionless ratio that comes from comparing the actual masses of the atom’s isotopes and averaging them according to how common they are in nature. The number you see on the periodic table for an element is this relative atomic mass.

The atomic mass unit, by contrast, is the unit used to express an actual mass. It’s a way to quantify how heavy something is, but it’s not the description of mass relative to other atoms. Atomic number is just the count of protons, and an isotope is an alternative form of the element with a different number of neutrons.