what does the 8 on top of a chemical symbol signify?
The 8 written on top of a chemical symbol signifies the atomic mass of an element. The atomic mass is the weighted average mass of all the naturally occurring isotopes of that element. It takes into account the mass of each isotope and the abundance of each isotope in nature.
To find the atomic mass of an element, you can refer to the periodic table. The atomic mass is usually listed below the element's symbol. It is represented by a decimal number since it is an average value.
Let's take an example. The chemical symbol for oxygen is O. The atomic mass of oxygen is approximately 16.00 atomic mass units (amu). The number 16.00 is the weighted average of the masses of all oxygen isotopes.
So, when you see the 8 written on top of a chemical symbol, it means that the atomic mass of that element is 8 amu.