Introduction Matter is described as anything that has mass and occupies space. Every matter is compose of different substances. There are a lot of substances that exist on planet.
That is why chemists use some sort of classification in which each substance would fit into their discrete groupings. Chemist use bonding types, electrical conductivity, melting and boiling point and physical properties to classify substances into four main groups, which are: • Metallic substances • Ionic compounds • Covalent molecular and; • Covalent network substancesMetallic substances are substances that are made up of one or more metal. They have regular 3D lattice of positively charged ions. Metallic substances are bond together by metallic bond which has strong electrostatic attraction between the positive ions and the delocalised electrons.
These delocalised electrons carry current giving metallic substance the ability to conduct electricity in solid or liquid form. Metallic substances are insoluble in water. Because of strong metallic bond, metallic substances have high melting point.It requires a very large amount of thermal energy to break this strong bond. Metallic substances are malleable; they can be hammered into various shapes.
They are also ductile; they can be drawn into thin wires. Metallic substances are very dense and hard. Ionic compounds are formed between a metal and non-metal/s. They have a regular 3D-crystalline lattice of cations and anions.
Cations are atoms that have lost an electron to become positively charged, while anions are atoms that gained an electron making them negatively charged.In an ionic compound, metal form the cations and non-metal/s form the anions. Ionic compounds are held together by ionic compound which has strong electrostatic attraction between cations or metals and anions or non-metal. This bond is responsible for having high melting point in ionic compounds.
Solid ionic compound does not conduct electricity because the charged ions are locked in place and are held together by the crystalline lattice that prevents ions to move freely.On the other hand, ionic compound in liquid form and in aqueous solution can conduct electricity because ions are dissociated and are free to move. Electrons in an ion compound are transferred from one element to another. Ionic compounds can be easily broken into pieces because of its brittleness. Covalent molecular substances are made up of non-metals only.
They exist as group of atoms called molecules. Molecules are particles that can exist and move independently of each other.
