Nitrogen group- All these elements have 5 electrons in thereoutermost shell

Nitrogen- is important to the chemical industry. It is used to make fertilisers, nitric acid, nylon, dyes and explosives.

Phosphorus- is used in flares and incendiary devices.

Arsenic- is a well-known poison. Arsenic compounds are sometimes used as rat poisons.

Antimony- is used in the electronics industry to make some semiconductor devices, such as infrared detectors and diodes.

Bismuth- metal is brittle and so it is usually mixed with other metals to make it useful.

Unupentium- At present, it is only used in research.

 

Oyxegen group- All these elements contain 6 electrons on the outermost shell

oyxegen-Oxygen gas is used for oxy-acetylene welding and cutting of metals.

Sulfur- is used in the vulcanisation of black rubber, as a fungicide and in black gunpowder.

Selenium- can be used to reduce the transmission of sunlight.

Tellurium- is used in alloys, mostly with copper and stainless steel, to improve their machinability. 

Polonium- is an alpha-emitter, and is used as an alpha-particle source in the form of a thin film on a stainless steel disc.

Livermorium- At present, it is only used in research. 

 

Halogens- All elemsnts contain 7 electrons on the outermost shell. 

fluorine- is was used for the development of the atom bomb.

Chlorine- kills bacteria.

Bromine- is used in many areas such as agricultural chemicals, dyestuffs, insecticides, pharmaceuticals and chemical intermediates. 

iodine- has many commercial uses. Iodide salts are used in pharmaceuticals and disinfectants.

Astatine- there are currently no uses for astatine outside of research.

Unuesptium- at present, it is only used in research.