Demonstrate a knowledge of chemical formulae and balanced chemical equations

• including covalent compounds

Covalent bonds form when atoms share electrons. Remember that electrons move very fast and thus can be shared, effectively filling or emptying the outer shells of the atoms involved in the bond. Such bonds are referred to as electron-sharing bonds. An analogy can be made to child custody: the children are like electrons, and tend to spend some time with one parent and the rest of their time with their other parent. Carbon (C) is in Group IVa, meaning it has 4 electrons in its outer shell. Thus to become a "happy atom", Carbon can either gain or lose four electrons. By sharing the electrons with other atoms, Carbon can become a happy atom,. alternately filling and emptying its outer shell. The molecule methane (chemical formula CH₄) has four covalent bonds, one between Carbon and each of the four Hydrogens. Carbon contributes an electron, and Hydrogen contributes an electron. The sharing of a single electron pair is termed a single bond. When two pairs of electrons are shared, a double bond results, as in carbon dioxide.

Formation of covalent bonds in methane. Carbon needs to share four electrons, in effect it has four slots. Each hydrogen provides an electron to each of these slots. At the same time each hydrogen needs to fill one slot, which is done by sharing an electron with the carbon.

Since there is no metal the second metal will have its ending modified by the ending “ide”.

A greek prefix is added to tell us the number of atoms present.

1 atom = mono, 2 atoms = di, 3 atoms = tri, 4 atoms = tetra, 5 atoms = penta,

6 atoms = hexa, 7 atoms = hepta, 8 atoms = octa, 9 atoms = nona, 10 atoms = deca

For Example: The prefix “mono” is used to distinguish Carbon Monoxide and Carbon Dioxide.

So3 is named Sulfur Trioxide

The formula for Dinitrogen Pentoxide is N2O5