There are many elements found on earth. Most of these elements are in some or the other way useful for the survival of the living organisms. Presently there are around 118 recognized elements. Scientists are still trying to find new elements and in order to ease their task they have classified the available elements as metals, metalloids and non metals. This classification is purely based on the physical and chemical properties of the elements. Majority of the elements fall under the category of metals.
Metals are generally solid at room temperature. Gold, silver, iron, copper etc are all examples and Mercury is the only exception which is liquid. Non metals may be solid, liquid or gas at room temperature. Gases like oxygen, hydrogen, nitrogen and other noble gases are all non metals. Solids like carbon, phosphorus, selenium and liquid like bromine are non metals.
Metals generally have 1-3 valence electrons meaning they can lose them easily to attain stability. Thus they are good reducing agents. Non metas normally have 4 to 8 electrons in the valence shell and so they accept or share electrons easily. This property makes them good oxidizing agents.
Generally they are sonorous and lustrous while a non metal is not so. Unlike non metals, they are good conductors of electricity and heat. They are malleable and ductile but non metals cannot be drawn into wires. This property lets metals like Gold, Silver, Iron, zinc to be useful in making jewelry, utensils and tools
There are a few elements called metalloids or semi metls. Boron, silicon, germanium, arsenic, antimony, and tellurium are all called metalloids because they exhibit few properties of metals and few properties of non metals. Silicon has a good luster but is not a good conductor. In the periodic table, they are positioned in between metals and non metals. Depending on the element they react with, their reactivity differs. Metalloids make good semi-conductors. Hence they are widely used in manufacture of electronic goods. Metalloids are often used as alloying agents and in making of glasses. Common alloys in everyday life