mean atomic weight

• 平均原子量

mean atomic weight的用法和样例：

例句

1. Atoms of the same element that differ in their atomic weight are called isotopes.
   具有不同原子量的同一种元素被称为同位素。
2. Electrons weigh very little, so they aren't even counted in the atomic weight.
   电子非常轻，因此在原子量中甚至没有计算它。