Is Matter around us Pure : Elements and compounds


Elements and Compounds                                                                                                                                            


Chemistry is the study of the structures, physical properties, and chemical properties of material substances. It is very important to understand that all gases, liquids, and solids are not the same. All are different in terms of their composition. This is the reason why the classification of the matter is very important.

Chemically matter can be classified into 3 categories: Elements, Compounds, and Mixtures. Here we are going to discuss two categories of matter: Elements and Compounds


Elements are species of atoms which have the same number of protons in their atomic nuclei. Although an element’s atoms have the same number of protons, they can have different numbers of neutrons and hence different masses. When atoms of the same element have different numbers of neutrons, they are known as isotopes. As of now, there are 118 elements, of which the first 94 are naturally occurring while the remaining 24 are synthetic elements.

Elements are complete chemical substances which relate to a single entry in the modern periodic table. Elements consist of one kind of atoms only. They cannot be broken down into simpler fragments and can exist as either atom or as molecules. Elements are represented by symbols which are assigned by IUPAC. For example, Oxygen is represented by O, Aluminium is represented by Al, etc.

Examples of some commonly used elements are Hydrogen (H), Boron (B), Carbon (C), Silicon (Si), Sodium (Na), Lead (Pb), Platinum (Pt), etc.


When two or more elements chemically combine in a fixed ratio by mass, the obtained product is known as a compound. Compounds can be defined as substances consisting of 2 or more different types of elements in a fixed ratio of its atoms. When the elements combine, some of the individual property of the elements is lost and the newly formed compound has new properties. Compounds are represented by their chemical formula. A chemical formula is an information about the proportions of atoms that constitute a particular chemical compound.

The chemical formula of water is H2O which shows two atoms of hydrogen and one atom of oxygen have combined to form one molecule of H2O. The chemical formula for common salt is NaCl which shows one atom of sodium and one atom of chlorine combine to form one molecule of NaCl.

Examples of some commonly used compounds and their molecular formula:

Name of the compound Formula of the compound
Alcohol C2H6O
Acetic Acid C2H4O2
Sulphuric Acid H2SO4
Ammonia NH3
Methane CH4
Nitrous oxide N2O
Salt NaCl

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Atoms and Molecules : Law of Chemical Combinations