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Chemistry - Atoms

There are three basic parts of an atom. They are the proton, neutron and the electron

The proton has a positive\((+)\) charge, the neutron has a neutral\((0)\) charge, and the electron has a negative\((-)\) charge



  • The number of protons is simply the atomic number of the chemical in the periodic table


  • The number of electrons in an atom is the number of protons so that it can have a neutral charge

  • But an atom may also lose or get electrons and that may cause it to be an ion


  • You can get the number of neutrons in each atom here

  • Or, you get the mass number of a chemical, that is the atomic weight rounded to the nearest ones, then subtract it by the number of protons

In example,

the atomic weight of carbon is \(12.0107\), so the mass number is \(12\)

mass number = number of protons + number of neutrons

number of neutrons = mass number - number of protons

number of neutrons = \(12-6\)

number of neutrons = \(6\) in a carbon atom



  • It is in the centre of the nucleus of an atom


  • It is also in the centre of the nucleus with the proton


  • The electron is special as it moves all around the nucleus because of the attraction of the protons. (It has a negative charge and proton has a positive charge, and they both will attract to each other like a magnet)

  • Its mass is about \(1000\) smaller than the proton

Note by Daniel Lim
2 years, 9 months ago

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Do add quantum no.s too Avishi Gupta · 11 months, 2 weeks ago

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i just han ana exam about it :D Ahmed Elshaer · 2 years, 9 months ago

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