Calculate the number of grams in 3.99 x 10 20atoms of aluminum.

0.018 grams

Explanation:

The number of moles (n) in such number of atoms of Aluminum must be calculated by dividing the number of atoms (nA) by Avagadro's number i.e.

n = nA ÷ 6.02 × 10^23atoms

The number of atoms of Aluminum in this question has been given as: 3.99 x 10^20 atoms.

n = 3.99 x 10^20 ÷ 6.02 × 10^23

n = 3.99/6.02 × 10^(20-23)

n = 0.663 × 10^-3

n = 0.000663moles

Next, we convert the mole value to mass in grams by using the formula;

mole = mass/molar mass

mass = mole × molar mass

Molar mass of Al = 27g/mol

mass (g) = 0.000663 × 27

mass = 0.0179

mass of Aluminum is 0.018grams