Protons have positive charge and account for half of the atomic mass, but is nearly 2000 times massive than the electron! Now, that doesn't mean the mass of a proton is huge. On the contrary, one proton weighs 1.673*10-21 kg! HINT: For ease of calculations, chemists generally take the mass of one proton to be 1 amu (atomic mass units). The proton and electron have the same amount of charge, thought its opposite in sign. In a neutrally charge atom (where the atom has no charge), the number of protons in the nucleus is the same as the number of electrons zooming around the nucleus. For example, a neutrally charge carbon atom has six protons and six neutrons.


Scientists have agreed that the type of atom (element) can be distinguished based on the number of protons, known as the atomic number. If we carefully study the Periodic Table, we can see that is it arranged in order of increasing atomic number, not by atomic weight.


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