Atoms are the smallest particles of matter. Their structure is discussed elsewhere in this site. Click to read more about the structure of the atom. Their are 112 different types of atoms. Substances that are made of only one type of atom are known as elements. Chemistry has its own language and all elements and compounds are represented by symbols. It is important to remember some of these symbols. Below is a table of the first twenty elements and their symbols.

Some common metals

Describe one unique property of each metal in the table above. A property is a characteristic of the substance. For example carbon dioxide gas is colourless and denser than air.

Notice that, sometimes, the symbol is the first letter of the element's name. For example Carbon has the symbol "C". When two elements start with the same letter, such as carbon and calcium, the second letter in the name is used. Calcium is given the symbol Ca. Note how the first letter is always a capital while the second is in lower case.

Sometimes the letters from the element's Latin or Greek name are used. For example Iron has the symbol Fe taken from its Latin name ferrum. Mercury has the symbol Hg, taken from its Latin name hydragyrum. Sodium is given the symbol Na, taken from its latin name natrium.

Compounds are written with the symbols of the elements that form them. For example, carbon dioxide has the formula CO₂. This indicates that one molecule of carbon dioxide has one carbon atom and two oxygen atoms.

Exercises