1.2.3 - Relative Atomic Mass

What is an isotope?

• Atoms of the same element with different numbers of protons

• Atoms of different elements with the same number of neutrons

• Atoms of the same element with different numbers of neutrons

• Atoms of different elements with the same number of protons

What is the isotopic abundance percentage?

• The percentage of an isotope's mass relative to the total mass of the element

• The percentage of an isotope's mass relative to the atomic mass of the element

• The percentage of an isotope present compared to the total amount of the element

• The percentage of the atomic mass of an isotope compared to the total isotopic mass

How do you calculate the weighted average atomic mass of an element?

• By adding the atomic masses of all isotopes

• By multiplying the atomic mass of each isotope by its relative abundance and then summing these values

• By dividing the atomic mass of each isotope by its isotopic abundance

• By summing the isotopic abundances of all isotopes

If an element has two isotopes, with isotopic masses of 10 u and 11 u, and their isotopic abundances are 20% and 80% respectively, what is the relative atomic mass of the element?

• 10.8 u

• 10.2 u

• 20.8 u

• 21 u

What does a 100% isotopic abundance mean for an element?

• The element has only one naturally occurring isotope.

• The element has multiple isotopes, but only one is found in nature.

• All isotopes of the element have the same atomic mass.

• The element is synthetic and does not occur naturally.

If an element's isotopic masses are 35 u and 37 u with isotopic abundances of 75% and 25% respectively, what is the calculated relative atomic mass?

• 35.5 u

• 36 u

• 35.75 u

• 36.5 u

Why is the relative atomic mass of an element not always a whole number?

• Because of the presence of isotopes with different masses

• Due to experimental errors in measuring atomic masses

• Because atomic masses increase in a non-linear fashion

• Because of rounding errors in calculations

Which of the following elements is likely to have a relative atomic mass closest to a whole number?

• An element with one dominant isotope

• An element with equally abundant isotopes

• An element with isotopes having very different masses

• An element with isotopes having similar but not equal abundances

If the isotopic masses of an element are 107.87 u and 109.9 u with isotopic abundances of 51.84% and 48.16% respectively, what is the relative atomic mass of the element?

• 108.9 u

• 108.87 u

• 109 u

• 108.5 u

What role does isotopic abundance play in determining the relative atomic mass of an element?

• It determines the number of isotopes an element has.

• It affects the weight each isotope contributes to the overall atomic mass.

• It is used to calculate the number of neutrons in an isotope.

• It determines the chemical reactivity of the element.