同位素[ahy-suh-tohps]是具有相同质子数但具有不同数量的中子的原子。换句话说，具有不同的原子量。同位素是单个元素的不同形式。 81种稳定元素有275种同位素。有超过800种放射性同位素，其中一些是天然的，一些是合成的。元素周期表中的每个元素都有多种同位素形式。单一元素的同位素的化学性质趋于几乎相同。例外是氢的同位素，因为中子的数量对氢核的大小具有如此显着的影响。同位素的物理性质彼此不同，因为这些性质通常取决于质量。该差异可用于通过使用分馏和扩散将元素的同位素彼此分离。除氢外，自然元素中最丰富的同位素具有相同数量的质子和中子。最丰富的氢形式是prot，它有一个质子而没有中子。
澳洲中央昆士兰大学Assignment代写：同位素在化学中的定义和例子
Isotopes [ahy-suh-tohps] are atoms with the same number of protons, but differing numbers of neutrons. In other words, the have different atomic weights. Isotopes are different forms of a single element. There are 275 isotopes of the 81 stable elements. There are over 800 radioactive isotopes, some of which are natural and some synthetic. Every element on the periodic table has multiple isotope forms. The chemical properties of isotopes of a single element tend to be nearly identical. The exception would be the isotopes of hydrogen since the number of neutrons has such a significant effect on the size of the hydrogen nucleus. The physical properties of isotopes are different from each other since these properties often depend on mass. This difference may be used to separate isotopes of an element from each other by using fractional distillation and diffusion. With the exception of hydrogen, the most abundant isotopes of the natural elements have the same number of protons and neutrons. The most abundant form of hydrogen is protium, which has one proton and no neutrons.