The molar mass of gold (Au) is approximately 196.97 grams per mole. To determine the mass of 7 atoms of gold, we need to calculate the mass of one atom and then multiply it by 7.
Mass of one atom of gold (Au): = Molar mass of gold / Avogadro's number = 196.97 g/mol / 6.022 x 10^23 mol^-1 ≈ 3.271 x 10^-22 grams
Mass of 7 atoms of gold: = Mass of one atom of gold x 7 ≈ (3.271 x 10^-22 grams) x 7 ≈ 2.289 x 10^-21 grams
Therefore, the mass of 7 atoms of gold is approximately 2.289 x 10^-21 grams.