Programmes/ Content/ Chemistry
Navigation

Introduction

Metal:

  • Metals are natural compounds of earth’s crust, in which they are generally found in the form of metal ores, associated both with each other and with many other elements.
  • Most metals are lustrous or shiny.
  • Most metals are hard but some are not.
  • Sodium and potassium are such metals that can be cut by knife.
  •  Mercury is a liquid metal at room temperature.
  • Tungsten is the hardest metal.
  • Caesium is considered to be the softest metal, and Lead is considered one of the softest metals.
  •  Gallium is liquid at body temperature, while solid (soft) at room temperature.
  • Calcium will react with water or moisture causing heat. If calcium comes in touch with any parts of body and eyes, it causes irritation and corrosion.
  • Metals are reducing agents.
  • Metals form mostly basic oxides but some are amphoteric.

Physical Properties of Metal:

  • All the metals are good conductors of heat and electricity.
  • Ductility is the ability of the material to be stretched into a wire. This ability allows metals to be drawn into wires and coupled with their durability, find applications as cable wires and for soldering purposes. Because Metal can be drawn into wires we can say that metals are ductile.
  • Malleability is the property of substances which allows them to be beaten into flat sheets. Aluminum sheets are used in the manufacturing of Aircrafts because of their lightweight and strength. Other metal sheets are used in automobile industries, for making utensils, etc. Therefore, metals are malleable.
  • Metals are sonorous because they produces a deep or ringing sound when struck with another hard object.
  • Usually, all the metals have a shiny appearance but these metals can also be polished to have a shiny appearance.

Chemical Properties of Metals:

  • Reaction with water: Only highly reactive metals react with water and not all the metals. For example, Sodium reacts vigorously with water and oxygen and gives a large amount of heat in the process. This is why sodium is stored in kerosene so that it does not come in contact with moisture or oxygen.
  • Reaction with acids: Hydrogen gas is produced when metals react with acids. For example, when zinc reacts with hydrochloric acid it produces zinc chloride and hydrogen gas.
  • Reaction with bases: Not all the metals react with bases and when they do react, they produce metal salts and hydrogen gas. When zinc reacts with strong sodium hydroxide it gives sodium zincate and hydrogen gas.
  • Reaction with oxygen: Metal oxides are produced when metals burn in the presence of oxygen. These metal oxides are basic in nature. For example: When a magnesium strip is burned in the presence of oxygen it forms magnesium oxide and when magnesium oxide dissolves in water it forms magnesium hydroxide.