Question

boron occurs naturally as two isotopes. what is the difference between these isotopes? they have different numbers of electrons and different charges. they have different numbers of neutrons and different charges. they have different numbers of protons and different mass numbers. they have different numbers of neutrons and different mass numbers.

Explanation:

同位素是具有相同质子数，不同中子数的同一元素的不同核素。质子数决定元素种类，所以同位素质子数相同，电子数也相同（原子呈电中性，电子数等于质子数），电荷数也相同。而中子数不同，质量数 = 质子数 + 中子数，所以质量数不同。

Answer:

They have different numbers of neutrons and different mass numbers.