Chemistry 6C Review

What is isotopic composition?

• The number of isotopes in a sample

• The mass of isotopes in a sample

• The charge of isotopes in a sample

• Relative abundance of isotopes in a sample

Define atomic mass.

• The mass of the nucleus of an atom.

• The average mass of atoms in a sample of an element.

• The mass of an individual atom of an element.

• The total mass of all the atoms in a sample of an element.

How is average atomic mass calculated?

• Weighted average of isotopes' masses

• Sum of isotopes' masses

• Median of isotopes' masses

• Mode of isotopes' masses

What is isotopic abundance?

• Relative amount of each different isotope of an element found in a sample

• The number of neutrons in an isotope

• The average mass of all isotopes of an element

• The total number of isotopes in an element

Explain isotope notation.

• Isotope notation is a way to represent the number of neutrons in an atom.

• Isotope notation is a way to represent an atom of a particular element, which includes the element's symbol, atomic number, and mass number.

• Isotope notation is a way to represent the number of protons in an atom.

• Isotope notation is a way to represent the number of electrons in an atom.

What is the relationship between isotopic composition and atomic mass?

• Isotopic composition and atomic mass are unrelated.

• The isotopic composition directly affects the atomic mass of an element.

• The atomic mass determines the isotopic composition of an element.

• The isotopic composition has no effect on the atomic mass of an element.

Why is it important to calculate average atomic mass?

• To determine the total number of atoms in an element.

• To calculate the number of neutrons in an element.

• To determine the atomic number of an element.

• To determine the weighted average mass of all the isotopes of an element.

What is the formula to calculate average atomic mass?

• Sum of (mass of each isotope * relative abundance) / total number of atoms

• Sum of (mass of each isotope * relative abundance) / total number of elements

• Sum of (mass of each isotope * relative abundance) / total number of isotopes

• Sum of (mass of each isotope * relative abundance) / total number of protons

If an element has two isotopes with masses 10 amu and 12 amu, and their abundances are 25% and 75% respectively, what is the average atomic mass of the element?

• 11.5 amu

• 9 amu

• 13 amu

• 10.5 amu

If an element has three isotopes with masses 14 amu, 15 amu, and 16 amu, and their abundances are 20%, 30%, and 50% respectively, what is the average atomic mass of the element?

• 14.5

• 15.5

• 15.3

• 16.5