When converting a number written as a percent into its decimal form, move the decimal ​ (a)   spaces to the ​ (b)   .

• 2
• left
• 1
• 3
• 0
• right

When mathematically calculating the weighted average, ​ (a)   the mass of the atom by its percent-abundance.

• multiply
• divide
• add

Select the numbers that need to have the decimal moved 2 places to the left.

3.05% written as a decimal would be

Besides being told this is the average atomic mass for gallium on the periodic table, what is at least one logical way you can be confident this is the correct answer?

After hearing Tyler's explanation for checking your answer, were you already on the right track? If not, identify a strategy to help you remember this logic in the future.

What unit do we use for the mass of an atom in this class?

• amu

• u

• Daltons

• g

If an element has 6 isotopes, how many times will you need to multiply in your average atomic mass calculation?

• 2

• 3

• 6

• 0

After the isotopes have been multiplied by their abundances as decimals, what is the last step to finish the average atomic mass calculation?

• add the products together

• add the products together then divide by the total number of isotopes

• add the products together then divide by 100

• multiply the products together

In this class, to how many decimal places do you need to round off your final answer for the average atomic mass?

• 0 - answers should always be whole numbers

• 1

• 2

• 3

• Answers should not be rounded