The mass of a single atom of an element X is 2.65×10−23 g. What could this element be?
One atom of the element X has mass = 2.65×10−23 g
Thus, 6.022×1023 atoms of element X have mass = 2.65×10−23×6.022×1023=16g
The element with gram atomic mass of 16, is oxygen (O).