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# Why are the masses of isotopes not whole numbers?

## Why are the masses of isotopes not whole numbers?

The atomic masses of most elements are not whole numbers, because they are a weighted average of the mass numbers of the different isotopes of that element, with respect to their abundances in nature.

## How does isotopes relate to atomic mass?

Each isotope of a given element has the same atomic number but a different mass number (A), which is the sum of the numbers of protons and neutrons. The atomic mass of an element is the weighted average of the masses of the naturally occurring isotopes.

Why are relative atomic masses not whole numbers?

The relative atomic mass of an element is a weighted average of the masses of the atoms of the isotopes. It takes account of the abundance of each of the isotopes of the element. relative atomic masses are often rounded to the nearest whole number, but are actually not whole numbers.

Why are the atomic masses listed in the periodic table not whole numbers quizlet?

Why are atomic masses of elements not generally whole numbers? The atomic masses listed on the periodic table are a weighted AVERAGE of an element’s isotopes. An element’s atomic number is the number of protons in its nucleus. Number of protons specifies atom type.

### Why are the atomic masses listed on the periodic table decimal numbers and not whole numbers?

Though individual atoms always have an integer number of atomic mass units, the atomic mass on the periodic table is stated as a decimal number because it is an average of the various isotopes of an element.

### Why do isotopes have different atomic masses?

Basic principles. Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.

What is the relationship of the mass number and isotopes number?

The number of neutrons is variable, resulting in isotopes, which are different forms of the same atom that vary only in the number of neutrons they possess. Together, the number of protons and the number of neutrons determine an element’s mass number.

Why is atomic weight not a whole number but mass number is always whole number?

Because the atomic weight is an average based on the percentage of atoms of each isotope in the naturally occurring isotopic mixture (Section 2.6, Example 2.2), atomic weights are not whole numbers even though atomic numbers and mass numbers are whole numbers. Isotopic masses also differ from whole numbers.

#### Is the mass of an isotope a whole number?

Is the mass of an isotope a whole number? Yes, it is a whole number because it is the sum of the number of protons and neutrons in an atom.

#### How are isotopes of the same element similar?

Isotopes are atoms of the same element that contain an identical number of protons, but a different number of neutrons. Despite having different numbers of neutrons, isotopes of the same element have very similar physical properties.

What is the difference between the mass number of an isotope and its atomic number?

While the mass number is the sum of the protons and neutrons in an atom, the atomic number is only the number of protons.

Do isotopes have different atomic masses?

Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.