Elements and the proton number

• The atoms of different elements are different from each other
• This is because they have different numbers of protons and neutrons
• Each element is made up of only one type of atom
• Atoms of different elements also have a different mass and size
• For example a carbon atom is 12 times heavier than a hydrogen atom
• The number of protons in the nucleus is known as the proton number
• The simplest atom is that of hydrogen which has the proton number of one
• It has one proton in the nucleus and no neutrons
• It electronically neutral as the proton is balanced by one electronic
• Helium comes next with two protons, two electrons and two neutrons

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