Principles of Science

Atoms are very small particles that make up everything including

humans, animals and the world around us.

An atom is made up of particles, which revolve around a nucleus.

The particles are protons, electrons and neutrons.

These particles are each in turn different. Protons have a positive

charge, electrons have a negative charge while neutrons are neutral

and carry no charge.

The only similarities, which 2 of the particles have, are protons and

neutrons and their mass is equal to the mass of an atom of hydrogen.

While scientifically we call this mass one atomic mass unit. The mass

of an atom depends on the amount of protons and neutrons the atom

contains and the arrangement of particles within the atom.

The arrangement of the particles within an atom depend on how they are

positioned because every atom has a nucleus which the protons and

neutrons occupy, while the electrons move around in a constant stable

orbit outside of the nucleus. However every electron in an atom do not

have the same amount of energy. The electrons, which are further away

from the nucleus, need more energy to move around the larger orbit.

The different sized orbits are grouped together in shells. The shell

is the group of orbits with similar energy. Each shell can hold up to

a certain number of electrons. In any atom the maximum number of

electrons in the outermost group of orbits is 8.

The maximum amounts of electrons, which can be occupied within a

shell, are as follows:

1st shell can hold a maximum of 2 electrons

2nd shell can hold a maximum of 8 electrons

3rd shell can hold a maximum of 18 electrons

4th shell can hold a maximum of 32 electrons

While the layout of the nitrogen atom can be seen with the different

particles and the different amounts of electrons can be seen in their

orbits around