Lesson 1.7 - Size Of Atoms
In this lesson:
Size of an atom
Atoms are very small.
They have a radius of about 0.1 nm (1x10-10 m).
Nucleus size
The radius of the nucleus only makes up 1/10,000 of the atom!
It therefore has a radius of about 1x10-14m! (That's 0.01 pico-metres!)
Nucleus mass
While the nucleus is tiny in comparison to an atom, it makes up almost all of the mass!
The atomic mass of electrons is very small - much less than that of a proton or neutron.
Atomic mass
The atomic mass is calculated as follows:
Atomic mass = number of protons + number of neutrons
Electrons are usually ignored because they are so small.
Atomic mass table
Particle
Atomic mass
Proton
1
Neutron
1
Electron
Very small
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