CHEMISTRY - Matter, Elements, Compounds

<b>Matter :-</b> Everything that is around us and the presence of which can be felt with the help of any of our five sense, i.e sight, touch, smell, hearing, and taste. Everything are matter. In fact, this whole universe is made up of only two things viz. matter and energy. Accordings to books Matter is defined as any things that occupies space, possesses mass and the presence of which can be felt by any one or more of our five senses.
Matter are physicaly classified as :-

1. Solids :- Any substance is said to be a solid if itvposses a definite shape and volume are known as Solids. Ex. Sugar, iron, gold, wood etc.

2. Liquids :- Any substance is said to be a liquid, if it possesses definite volume but no definite shape. They take up the shape of vessel in which they are put, Ex. Water, milk, oil, alcohol etc.

3. Gases :- Any substances is said to be a gaseous if it neither possesses a definite volume nor a definite shape. This is because they fill up the whole vessels in which they are put , Ex. Air, oxygen,hydrogen etc.

:- Matter are chemicaly classified as :-

1. Homogeneous :- A material is said to be a homogeneous, if it has uniform compositionand identical properties throughout.

2. Heterogeneous :- A material is said to be a heterogeneous, if it is consist of only one phase. On the other hand, a material is said to be a heterogeneous if it consist of a number of phases.

<b> Elements :-</b> An element is usually defined as the simplest form of a pure substance with definite physical and cemical properties and which can neither be broken into nor built from simpler substances by any chemical or physical method.

Elements are further sub-divided as :-

1. Metals :- Metals are those elements which reflect light and hence possess lustre. They are good conductors of heat and electricity, malleable and ductile and possess high density . Ex. Copper, silver, gold, iron, lead, tin etc.

2. Non - Metals :- Non-metals are those elements which do not reflect light and hence do not possess lustre. Further, they are brittle, poor conductors of heat and electricity.

3. Metalloids :- Metalloids are those elements which possess the characterstics of both i.e metal as well as non - metals. Ex. Arsenic, antimony, bismuth etc.

<b> Compounds :-</b> A compound is a pure substance containing two or more than two elements combined together in fixed proportion by mass and which can be decomposed into its constituent elements by suitable chemical method. Further, the properties of compound are completely different from those of its constituent elements. 

Compounds are further classified as :-

1. Organic Compounds :- Organic compounds are the compounds containing carbon and a few other element like hydrogen, oxygen, nitrogen etc. These were originally obtained only from animals and plants.

2. Inorganic Compounds :- These are the compounds containing any two or more element out of more than 114 elements known so far. These are usually obtained from minerals and rocks.