They indicate groups of elements which often (but not always) share common properties. (cf. http://en.wikipedia.org/wiki/Periodic_table#Groups)
One of the common characteristics in a group is that they share the same number of electrons on the outer shell.
groups are the vertical columns on the periodic table
The columns on the periodic table are called Groups.
There are 8 A columns on the periodic table. They are the two columns of the s-block and the six columns of the p-block.
The columns are known as groups.
The columns are known as groups.
groups are the vertical columns on the periodic table
The vertical columns of the periodic table are called groups or families.
The columns on the periodic table are called Groups.
The word for columns in the periodic table is groups. They are also referred as families.
The vertical columns in a periodic table are called Groups.
there are 18 columns
There are 18 columns.
There are 8 A columns on the periodic table. They are the two columns of the s-block and the six columns of the p-block.
the vertical columns in the periodic table are known as groups.
The columns are known as groups.
The columns are known as groups.
the columns