1. Convert milligrams to grams:

* 1 gram (g) = 1000 milligrams (mg)

* 5.88 mg * (1 g / 1000 mg) = 0.00588 g ClF3

2. Calculate the molar mass of ClF3:

* Cl: 35.45 g/mol

* F: 19.00 g/mol

* Molar mass of ClF3 = 35.45 + (3 * 19.00) = 92.45 g/mol

3. Calculate the moles of ClF3:

* Moles = mass / molar mass

* Moles of ClF3 = 0.00588 g / 92.45 g/mol = 6.36 x 10^-5 mol ClF3

4. Determine the moles of F atoms:

* There are 3 moles of F atoms for every 1 mole of ClF3.

* Moles of F = (6.36 x 10^-5 mol ClF3) * (3 mol F / 1 mol ClF3) = 1.91 x 10^-4 mol F

5. Calculate the number of F atoms:

* Use Avogadro's number (6.022 x 10^23 atoms/mol)

* Number of F atoms = (1.91 x 10^-4 mol F) * (6.022 x 10^23 atoms/mol) = 1.15 x 10^20 atoms of F

Therefore, there are approximately 1.15 x 10^20 atoms of fluorine in 5.88 mg of ClF3.