Isotopes and Average Atomic Mass

Front

What is an isotope?

Back

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons, resulting in different atomic masses.

Front

How do you calculate the average atomic mass of an element with multiple isotopes?

Back

To calculate the average atomic mass, multiply the mass of each isotope by its relative abundance (as a decimal), then sum these values.

Front

What is the formula to find the number of neutrons in an atom?

Back

Number of neutrons = Atomic mass - Atomic number.

Front

If an element has an atomic number of 5, how many protons does it have?

Back

It has 5 protons, as the atomic number is equal to the number of protons.

Front

What is the average atomic mass of an element with isotopes of 49.9461 amu (4.35%), 51.9405 amu (83.79%), 52.9407 amu (9.50%), and 53.9389 amu (2.36%)?

Back

The average atomic mass is 51.99 amu.

Front

What is the significance of the atomic number in relation to isotopes?

Back

The atomic number determines the element and is equal to the number of protons in the nucleus, which remains constant for all isotopes of an element.

Front

How do you express the relative abundance of an isotope as a decimal?

Back

To express relative abundance as a decimal, divide the percentage by 100.

Front

What are the two primary isotopes of copper and their relative abundances?

Back

The two primary isotopes of copper are copper-63 (30.8%) and copper-65 (69.2%).

Front

What is the average atomic mass of copper based on its isotopes?

Back

The average atomic mass of copper is 64.4 amu.

Front

What is the relationship between protons, neutrons, and electrons in a neutral atom?

Back

In a neutral atom, the number of protons equals the number of electrons.