Periodic Table
Groups and Periods in the Periodic Table
1) Each vertical column is called a group.
a. There are 18 groups.
b. Elements with similar chemical characteristics are grouped together.
c. Each group contains elements with same number of valence electrons.
2) Each horizontal row is called a period.
a. There are 7 periods.
b. Each period contains elements with same number of shells which are filled with electrons.
c. Each period contains elements with chemical and physical characteristics which change progressively from metal to non-metal.
d. Elements are arranged according to the order of their proton number which increases horizontally.
Group
|
Name of group
|
Group 1
|
Alkali metals
|
Group 2
|
Alkaline earth metals
|
Group 17
|
Halogens
|
Group 18
|
Noble gases
|
Group 3 to 12
|
Transition elements
|
Group 1 - very reactive metals
Group 18 - highly unreactive noble gases (chemically inert)
All transition elements - have metal characteristics.