The number of known elements has increased over the years. There were only 63 known elements in 1869. That was when Mendeleeff organized the first periodic table after 20 years of research. The modern periodic table has 112 elements, and there will be more.

There are three classifications for the elements. There are metals, nonmetals and metalloids. The pure elements are rarely found in nature. The elements are typically combined with one another to form compounds. Gold and platinum are two that are found pure in nature.

Metals are usually solids at room temperature, good conductors of heat electricity, are ductile and malleable. They make up the largest part of the periodic table. The nonmetals have the opposite properties of metals. There are seventeen (17) nonmetals. Eleven of these are gases, one is a liquid and five are solids at room temperature. Nonmetals are poor conductors of heat and electricity; they are neither malleable nor ductile. The seven (7) metalloids are the smallest class of elements. They have some properties like metals and some properties like nonmetals. Silicon, Si, in Group 4a is one of the most well known semimetals or metalloids.

Metals like iron usually have high melting points. However, mercury, Hg, has a low melting point.

Metals can be hammered into thin sheets this makes them malleable. Gold is one of the most malleable metals. Gold foil is used for decoration.