Google. 1  Crunch Report | Juicero Runs Out Of Juice. 2  Googleâs Search app on iOS gets a Twitter-like Trends feature, faster Instant Answers. 3  Google reveals the top things people want to find out âHow toâ do. 4  Browse more...
The definition of an atomic number is the number of protons in the nucleus of an atom of an element. Three for lithium and 20 for calcium are each an example of an atomic number.
Element showing its atomic number and mass number. Atomic number is used to define the type of element a material or substance is. It is the number of protons present in an elementâs nucleus. The atomic mass, on the other hand, is the number of both the protons and neutrons present in the nucleus of the element. Electrons do not usually weigh much, so the atomic mass is calculated by adding the number of protons to neutrons. It is also referred to as the atomic weight.