1. Find the molar mass of silicon:

* The molar mass of silicon (Si) is approximately 28.09 g/mol. This means that one mole of silicon atoms weighs 28.09 grams.

2. Convert atoms to moles:

* Avogadro's number tells us that there are 6.022 x 10^23 atoms in one mole of any substance.

* Divide the given number of silicon atoms by Avogadro's number to find the number of moles:

(1.63 x 10^21 atoms) / (6.022 x 10^23 atoms/mol) ≈ 0.00271 moles

3. Calculate the mass:

* Multiply the number of moles by the molar mass of silicon:

(0.00271 moles) * (28.09 g/mol) ≈ 0.0762 g

Therefore, the mass of 1.63 x 10^21 silicon atoms is approximately 0.0762 grams.