Question

Why are atomic masses on the Periodic Table written in decimals when they are based on mass numbers that can be whole numbers?

Answer 1

To allow for equations and problems in chemistry to be as precise as possible. When experiments are conducted, and even if the number is the slightest bit off, the problem or experiment could be impacted very negatively. It allows for complete accuracy to ensure nothing goes wrong, since chemistry is very touchy and risky when dealing with extremely unsafe elements.