I believe the answer is A. please let me know if i am correct or not.
Answer: .309 moles (rounded to the nearest thousandth)
Explanation: divide your atoms by (6.022 x 10x^{23})
Answer:

Given:
Mass = 11.29 g
Volume = 2 cm³
To Find:
Density of unknown metal
Explanation:
Formula:

Substituting value of mass & volume in the formula:

31,000 milligrams is equal to 31 grams