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Atomic Structure Links


Properties of Subatomic Particles

(protons, neutrons and electrons)



Proton (p+) is positively charged particle of the atomic nucleus. The atomic number of an element represents the number of protons in the nucleus.

 Electron (e-) is negatively charged particle that can occupy a volume of space (orbital) around an atomic nucleus. All atoms of an element have the same number of electrons (i.e. any Chlorine atom is going to have 17 electrons). Electrons can be shared or transferred among atoms.

 Atoms have an equal number of protons and electrons; therefore, they have a no net charge.

 Ion is an atom that has gained or lost one or more electrons, thus becoming positively or negatively charged.

 Neutron is an uncharged particle of the nucleus of all atoms EXCEPT hydrogen. For a given element, the mass number is the number of protons and neutrons (nucleons) in the nucleus.

 Isotope is one of two or more forms of atoms of an element that differ in their number of neutrons. They have the same atomic number (same number of protons and electrons), but a different mass number due to more or fewer neutrons.

Particle              Charge         Relative Charge** Mass    Relative mass**                      Location   
Proton +1.60 x 10-19 C +1 1.672 x 10-24 g

1 amu

Electron -1.60 x 10-19 C -1 9.05 x 10-28 g 0 amu ~(1/1840 amu) electron cloud (orbital)
Neutron neutral 0 1.674 x 10-24 g 1 amu nucleus

**Using relative charges and masses are used to keep calculations simple. 

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