1.4 The Periodic Table

REVISION NOTES

IGCSE Edexcel Chemistry

1.4.1 Understand how elements are arranged in the Periodic Table:

Elements on the periodic table are arranged in order of increasing atomic number.

GROUPS

Vertical columns in the table
Group number shows the number of valence (outermost shell) electrons
- E.g. elements in group 2 have 2 electrons in the valence shell
The final group is called group 18 or 8 or 0

PERIODS

Horizontal rows in the table
Period number shows the number of electron shells in an atom
- E.g. elements in period 2 have two electron shells

1.4.2 Understand how to deduce the electronic configurations of the first 20 elements from their positions in the Periodic Table

Deducing total number of electrons

Each electron shell can accommodate a fixed number of electrons

Electronic Configuration of First 20 Elements

1.4.3 Understand how to use electrical conductivity and the acid-base character of oxides to classify elements as metals or non-metals

1.4.4 Identify an element as a metal or a non-metal according to its position in the Periodic Table

In general,

1.4.5 Understand how the electronic configuration of a main group element is related to its position in the Periodic Table

Period number: number of electron shells

Group number: number of electrons in the outer shell

1.4.6 Understand why elements in the same group of the Periodic Table have similar chemical properties

The chemical properties of an element depend on the number of electrons in the outer shell
Elements in the same group have same number of electrons in the outer shell
Therefore, elements in the same group have similar chemical properties

1.4.7 Understand why the noble gases (Group 0) do not readily react

Noble gases (group 0) have 8 electrons in their outer shell (except for helium, which has 2)
Noble gases reach octet rule, meaning that they have full electron shells
They do not lose or gain electrons easily
Therefore, they are unreactive and do not easily form molecules