2 .1 understand the terms group and period
2.2 recall the positions of metals and non-metals in the Periodic Table
2.3 explain the classification of elements as metals or non-metals on the basis of their electrical
conductivity and the acid-base character of their oxides
2.4 understand why elements in the same group of the Periodic Table have similar chemical properties
2.5 understand that the noble gases (Group 0) as a family of inert gases and explain their lack of
reactivity in terms of their electronic configurations
The periodic table is a method of classifying elements into groups and periods.
 group = vertical column of elements; within a group there are distinct chemical similarities but also gradual changes in properties as we will see in groups 1 and 7.
 period = horizontal row of elements, from an alkali metal to noble gas.
Metals and non-metals
All elements in the periodic table are divided up into metals and non-metals. The metals are found to the left and the middle whilst the non-metals on the right.
Metals
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metals usually have high melting and boiling points; they are all solids except mercury;
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metals are malleable
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metals are good conductors of heat and electricity;
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metals are usually shiny (most are also silvery);
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metals are ductile
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their oxides are basic (high pH)
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Non-metals
variable melting and boiling points but usually lower than in metals; most non-metals are either solids or gases;
non-metals are brittle;
non-metals are poor conductors of heat and electricity (except graphite);
non-metal oxides are acidic (low pH)
Relationship between position in Periodic Table and electronic configuration
Relationship between electronic configuration of elements and their position in the Periodic Table:
 an element’s group number is the same as the number of valence electrons in its outer most shell.
 an element’s period number is the same as the number of shells which have electrons on them or the number of the shell being filled .
Elements in same group have similar chemical properties
The chemical properties of an element depend on the number of electrons in its most outer shell .
As all elements in the same group have the same number of valence electrons all elements in the same group will have similar chemical properties. For instance all elements in group 1 have 1 electron in their last shell and because of that are all very reactive.
Noble gases are unreactive
The elements in the last group, group 0, are inert gases. They are unreactive because they have a full outer shell (2 electrons in the case of helium and 8 electrons in the other noble gases) unlike the elements in the other group.
Section 2a the periodic table 1 | P a g e

Section 2a the periodic table 2 | P a g e