By: Jhordian Maxwell
the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
The group number is an identifier used to describe the column of the standard periodic table in which the element appears. Groups 1-2 (except hydrogen) and 13-18 are termed main group elements. Groups 3-11 are termed transition elements.
Real life uses
It is used in thermometers because it has a large thermal expansion which is constant over a large temperature range although it is being phased out in favour of safer liquids.
It is also used in barometers an manometers due to its high density. From this it has also become a way of measuring pressure in millimetres of mercury.
It has also been used as liquid electrolyte for the production of chlorine and sodium hydroxide from the electrolysis of brine but is again being phased out in favour of safer alternatives.