You can watch the YouTube Video below to have an even clearer idea about the properties of pure metals and the reasons why metals are often used in the form of alloys. The solder material is usually an alloy of tin and lead, and it has a lower melting point than most metals.Ĭan you draw simple diagrams to show the difference in the arrangement of atoms between copper and bronze? YouTube Video Tutorial on Physical Properties of Pure Metals and Alloys The main method used in the industry to join two metal parts together is through the use of soldering. It is commonly used to make ornaments such as key chains and decorative displays because it looks more beautiful than pure tin itself. Pewter is an alloy of tin, antimony and copper. 3) To improve the appearance of of metals Source: Paper 2, Nov 2011 GCE O-Level Pure Chemistry Examination 2) To make metals more resistant to corrosionĬoins that we used in our everyday lives are made of cupronickel, which is an alloy of copper and nickel.
Īnswer: The ‘sea’ of delocalised valence electrons in uranium are free moving and they act as charge carriers and move throughout the metallic structure. (ii) Explain what happens when an electric current passes through uranium.
It is a silvery-grey metal in the actinoids series of the periodic table.Īnswer: Strong electrostatic forces of attraction between the positively uranium ions and the ‘sea’ of delocalised electrons in the giant metallic lattice structure. Uranium is a chemical element with the symbol U and atomic number 92. This is modified from a question in Paper 2 (Written Paper) of the Nov 2011 GCE O-Level Pure Chemistry Examination in Singapore.
Let’s take a look at a potential question which you might be tested in the Chemistry examination.
corrode easilyĪs such, we often use alloys instead of the pure metals. Pure metals may react with air and water i.e.Pure metals have many useful properties but they are not widely used because of two main reasons: (free moving) and act as charge carriers which help to conduct electricity and heat. These ‘sea’ of delocalised electrons are mobile The valence (outermost shell) electrons delocalised into the empty spaces (‘sea’) and are able to move freely within the metal lattice. ‘Sea’ of delocalised electrons surrounding the positively charged metal ions in the giant metallic lattice structure 4) Good conductors of electricity (and heat) As such, pure metals are known to be soft, malleable and ductile. When a force is applied to a metal, the layers of metal atoms can slide past each other. In pure metals, same size atoms are packed closely together in a regular pattern. Ductility refers to the ability to be stretched or drawn into wires without breaking. Malleability refers to the ability to be beaten or hammered into shapes without breaking. As such, there is large number of atoms per unit volume i.e. Physical Properties of Metals 1) Usually have high densitiesĪtoms in a metal are packed tightly in layers and are held together by strong metallic bonds. These physical properties can be easily explained by looking at the structures of metal. Good conductors of electricity (and heat).Usually have high melting points and boiling points i.e.In general, metals have the following physical properties: Titanium and zirconium are also commonly used for making aircraft and space shuttle parts. Copper is widely used in metal wires and cables. Metals are commonly being used in our everyday lives.įor example, silver and gold are commonly used as jewellery because of their shiny appearance. Is Iron Man made of a Pure Metal or An Alloy?