Atomic Theory

This video shows how the 92 naturally occurring kinds of atoms are listed from the lightest, hydrogen, to the heaviest, uranium, on the Periodic Table. The table's 7 rows and 18 groups are explained, as well as the table's division into metals and non-metals. Because Atomic Number is not introduced, it is a good starting video before atomic structure is covered and good for elementary school as well.

Watch how two hydrogen atoms collide and stick together to make a hydrogen molecule, H2. See how hydrogen atoms collide and chemically bond with oxygen to form water, H2O, with nitrogen to form ammonia, NH3, and with carbon to form methane, CH4. The chemical formula of these substances are explained, and the connection between the microscopic molecules that make up a substance and its macroscopic properties is shown. Also, the difference between an element and a compound is explained.

This video starts with a one-metre tall boy, then zooms in with a magnification of 10 in a series of steps to smaller and smaller objects till we can see an individual atom. On the way we encounter red blood cells, an anthrax bacterium, a flu virus, a DNA molecule, a sugar molecule, and finally a hydrogen atom.

This video shows how oxygen atoms can form double bonds, and nitrogen atoms can form triple bonds to make diatomic gaseous molecules. But carbon atoms can't form a quadruple bonds, instead bonding to make a network solid. The role of O2, N2 and CO2 in breathing and respiration is explored, and more complex molecules are introduced.

This video shows how all atoms are made of protons, neutrons (in the nucleus) and electrons (outside the nucleus). The positive charge of the protons and the negative charge of the electrons create an attractive force that holds the atom together. The number of protons in the nucleus determines which element the atom is. For example, all carbon atoms have 6 protons in their nuclei. Because neutral atoms carry no overall charge, the number of protons and electrons must be equal, thus cancelling out their charges. Electrons are wrapped around the nucleus in shells, with definite rules governing how many electrons each shell can hold. When atoms collide with each other, their outer shells come into contact with each other, so the number of electrons in an atom's outer shell is incredibly important. This number of electrons determines the properties of the atom.