Isotopes and Average Atomic Mass

Front

What is an isotope?

Back

An isotope is a variant of a chemical element that has the same number of protons but a different number of neutrons, resulting in a different atomic mass.

Front

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

Back

The average atomic mass is calculated by taking the weighted average of the masses of all the isotopes, considering their relative abundances.

Front

What is the relationship between atomic mass and the number of neutrons in an isotope?

Back

The number of neutrons can be found by subtracting the atomic number (number of protons) from the atomic mass (rounded to the nearest whole number).

Front

If an element has an atomic number of 6 and an atomic mass of 12, how many neutrons does it have?

Back

It has 6 neutrons (12 - 6 = 6).

Front

What does it mean if an isotope is more abundant than others?

Back

It means that a higher percentage of the element's atoms are of that particular isotope compared to the others.

Front

What is the average atomic mass of an element with isotopes of 10 amu (20%), 11 amu (30%), and 12 amu (50%)?

Back

The average atomic mass is calculated as (10 * 0.20) + (11 * 0.30) + (12 * 0.50) = 11.6 amu.

Front

What is the significance of the average atomic mass in chemistry?

Back

The average atomic mass helps predict the behavior of an element in chemical reactions and is used in stoichiometry.

Front

How does the presence of isotopes affect the average atomic mass of an element?

Back

The presence of isotopes with different masses and their relative abundances directly influence the calculated average atomic mass.

Front

What is the atomic mass unit (amu)?

Back

The atomic mass unit (amu) is a standard unit of mass used to express atomic and molecular weights, defined as one twelfth of the mass of a carbon-12 atom.

Front

Why can't the average atomic mass be determined if only the masses of isotopes are known without their abundances?

Back

Without the abundances, you cannot calculate the weighted average, which is necessary to find the average atomic mass.