It is usually thought that nature is just our immediate surrounding .However, the nature is must vast because it includes whole universe which is composed of innumerable star sytems and all inter stellar spaces ,containig countless things .Every thing of the nature , small or large ,solid,liquid or gas ,living or non- living ,is composed of matter or matters. The matter undergoes change in the nature and the process affecting the changes invoves energy and its conversion . Matter ;If we have to understand the nature and functioning of the living matter , we must know something about its chemical nature and the process affecting the changes involves energy and its conversion .Anything that occupies space and has mass, is called a matter . The matter may assume solid ,liquid or gas state .For example , water is a liquid state , ice is its solid state and steam is its gas state. State of a matter depends on the prevailing temperature .Water ,for example,is liquid or gas state .State of a matter depends on the prevailing temperature .Water , for example, is liquid within temperature range of above0 degree to 10 degree c.Below this range it forms steam [water vapours] and is a gas.However ,regardless of the state in which it exists ,it has the same chemical composition ,h2o .This is true with all matters . Type and composition of a matter. A matter may be an element ,compound or mixture .An element is akind of matter which cannot be broken down into two or more different kinds of atoms .Iron , sulphur, calcium , iodine oxygen and hydrogen are typical examples of elements . Elements are commonly indicated by their abbreviation called chemical symbols [eg] Fe for the iron ,S for sulphur ,Ca for calcium ,Ifor iodine ] .Any of these elements can be broken down into smalest divisible unit called atom .This unit holds all the chemical characteristics of its element . Thus , atom is the building block of an element . More than 100 types of atoms are known .Therefore there more than 100 elements . An element has a sub atomic structure which is which is composed of electrically charged particles of three kinds,electron ,proton and neutron .The electro is negatively charged , proton positively charged and neutraon uncharged [neutral] .The number of proton is equal to the number of electrons in an atom of an element .An atom has a central part called nucleus which is surrounded by orbit[s] or circle[s] .The proton and neutron are presented in the nucleus but the electrons are present in orbit[s] ,revolving round the nucleus The number of proton ,neutron , and electron is fixed for every element ;some element may lack neutron , for example hydrogen[H] .The hydrogen has one electron in the orbit and one protons in the nucleus which lacks neutron .The hydrogen represent the simplest atom . There is another atom, allied to hydrogen atom ,called heavy hydrogen or deuterium .Like hydrogen ,its atom has one proton in nucleus and one electron in orbit but its nucleus also contains one neutron .There fore , it [deuterium] is heavier than hydrogen.
No comments:
Post a Comment