Final answer:
The atomic mass of an oxygen atom as listed on the periodic table is 15.999 amu, which is also its molar mass in grams per mole.
Step-by-step explanation:
The atomic mass of an oxygen atom, as listed on the periodic table, is 15.999 atomic mass units (amu). In chemistry, the atomic mass listed in the periodic table often matches the molar mass of the element when expressed in grams per mole (g/mol). Therefore, the molar mass of an oxygen atom is also 15.999 g/mol. This means that if you have 1 mole of oxygen atoms, it would weigh approximately 15.999 grams.