Made by: M. Fahd-Un-Nabi Khan USMAN PUBLIC SCHOOL XI-O
Elements An element is a substance which cannot be split into two or more substances by chemical means The smallest possible particle of an Element that can take part in a chemical change is called an ATOM.
Compounds containing 2 or more Compound is substance elements chemically joined together. e.g. Magnesium is an element; oxygen is an element – they can only be combusted to form magnesium oxide (MgO) compound. Ions or molecules make up compounds Ions are atoms having electrical charge, e.g. NaCl made up of 2 ions; positively charged Na, negatively charged Cl.
Molecules Molecule is group of two or more atoms chemically joined together, e.g. chlorine molecule has 2 chlorine atoms. Molecules can be either ELEMENTS or COMPOUNDS. E.g. MgO is a compound, but Cl2 is an element
Mixtures 2 or more substances which are not chemically joined t ogether e.g. Iron in Sulphur powder. Can consist of: Elements (Iron & Sulphur powder) Compounds (Salt in water - salt & water are both compounds) Elements + Compounds (Air; N2, O2, H2O)
Difference between Compounds and Mixtures MIXTURE COMPOUNDS Constituent substances can Constituent substances can be separated easily by be separated only by chemical physical means means Its physical and chemical Its physical and chemical properties are an average of properties are individual and substances in it not the result of its elements A mixture’s proportion can A compound’s proportion vary cannot vary Little or no energy is involved Energy is usually involved when Mixture is formed when a Compound is formed
Diffrentiation between Pure andMixtures Pure Substances (elements, compounds) 1) Fixed composition 2) Fixed Mp/Bp 3) Produces only 1 spot on chromatogram 4) All molecules same (equal) Mixture 1) Variable Composition 2) Variable Bp/Mp 3) 2 or more spots on Chromatogram 4) 2 or more different molecules