Metals and Non-Metals:
In this chapter we will learn about:
Properties of Metals and Non metals
Broadly speaking, all elements in the periodic table can be classified as Metals or Non-Metals. Majority of elements in the periodic table are metals.
Elements that react to form positive ions in their chemical reaction are called metals. Elements that do not form positive ions in their chemical reaction are non-metals.
Properties of Non metals
Metals conduct energy in the form of heat.
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Metals are good conductors of heat.
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Metals conduct electricity.
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Metals are also malleable (they can be pressed in to thin sheets and bent in to different shapes).
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Metals have high density.
Metals have shiny surface.
Metals are usually very strong.
Metals have very high melting points.
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Metal elements are found towards the left and bottom of the periodic table.
Properties of Non metals
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Non-metal often have low density.
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Most non-metals are not very strong.
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Non-metals are very brittle.
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Non-metal usually have low melting and boiling points.
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Non-metals are poor conductors of heat and electricity.
Non-metals are generally dull in appearance.
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Non-metal elements can be found towards the right and top-right of the periodic table.
What are "Groups" in the periodic table? Groups are the "columns" in the periodic table. They are numbered in increasing order, going from left to right. So, you will find "Group 1" to the left of "Group 2". However, "Group 0" is an exception as it is the right-most column in the periodic table.
What are "Periods" in the periodic table? Periods are the "rows" in the periodic table. They are numbered in increasing order, going from top to bottom.
Group 0 – Noble Gases
The elements in Group 0 of the periodic table are also called noble gases.
You can find them in the right-most column of the periodic table.
Noble gases are not reactive, and, therefore, do not easily form molecules. This is because their outer most shells already have the maximum possible number of electrons.
Noble gases exist as single atoms.
They have very low melting and boiling points.
They are monatomic, colourless, non-flammable gases.
Helium is the first element of this group. It is lighter (less dense) than air, and used in balloons.
Group 1 – Alkali Metals
The elements in the “Group 1” of the periodic table are called the alkali metals because they form hydroxides that form alkaline (pH > 7) solutions in water.
Group 1 elements are placed in the left-most column of the periodic table.
Lithium, Sodium, Potassium and Rubidium all belong to this group.
Group 1 elements have only 1 electron in their outermost shell. This makes them very reactive.
Remember: Potassium is the most reactive metal in the reactivity series.
Alkali metals are soft. They can be cut with a sharp knife.
They are good conductors of electricity and heat.
Alkali metals have lower melting and boiling points compared to other metals.
Alkali metals have low density.
Group 7 – Halogens
The elements in Group 7 are known as the halogens.
Elements in this groups are Fluorine, Chlorine, Bromine, Iodine and Astatine.
Fluorine and chlorine are both gases at room temperature.
Bromine is a liquid, and Iodine and Astatine are solid at room temperature.
Chlorine is a pale-green gas, Bromine is brown and Iodine is black.
Group 7 elements have seven electrons in their outer shell.
All halogens naturally exist as diatomic molecules. Here, diatomic means having two atoms.
Each molecule is made up of a pair of atoms.
In group 7, the melting and boiling points increase as you go down the group.
Transition metals
Transition metals are placed in the groups between the "Group 2" and "Group 3" of the periodic table.
The transition metals are hard and strong.
They are good conductors of heat and electricity.
The transition metals have high melting points and high density.
They are less reactive. They do not react quickly with water or oxygen.
Transition elements are very useful as catalysts in the industry.
Transition metals form coloured ions and compounds.
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