Question

why oxygen was rejected as standard?​

Answer 1

This means that determining the weight percentage in an element oxide will tell you its formula, and therefore the atomic mass of that element. Since hydrogen is the lightest element, and oxygen weighs about 16 times as much as hydrogen, the atomic weight standard for about a century was “oxygen = 16 exactly.”Oct 9, 2018

Answer 2

Answer:

since it is the lightest elements, therefore it was arbitrarily assistant a mass of 1 and other elements were assigned masses relative to it