The Periodic Number Of Element
#The number of shells occupied with electros in its atom
Group 18 Element
# insoluble in water # low density
# cannot conduct electricity # colourless & unreactive
# poor conductor of heat # exist in monoatomic gases
- Helium # to cool the coils in body scanners in medical field
- Neon # advertising light on billboard and television tubes
- Argon # used in filament bulb & provide an inert atmosphere for welding at high temperature.
- Krypton # used in laser to repair retina & to fill photographic flash lamps.
- Radon # used to treat cancer patients
- Xenon # used in bubble chamber in atomic and making rlrctrin tubes and stroboscopic
GROUP 1 ELEMENTS
Going Down Group 1
- atomic radius increase
- density increase
- melting and boiling points decrease
- poor conductor of heat # poor electric conductor
- low melting & boiling points # called as halogen (salt former).
- Fluorine # pale yellow gas
- Chlorine # greenish-yellow gas
- Bromine # reddish-brown liquid
- Iodine # purplish-black solid
Going Down Group 17
- increase in size # higher density
- less reactive # increase the atomic radius
- Increase melting & boiling points # decrease the force of attraction
Elements In A Period
Across Period 3
- the proton number increasesby one unit from one element to the next element,
- all atoms of the elements have three shells occupied xith electron.
- the number of valemce electrons each atom increases from 1 to 8.
- all the elements exist as solid except chlorine and argon which are gases.
- the atomic radius of elementsdecreases.
- the electronegativity of element decrease.
Uses Of Semi-metal In Industries
- Silicon and germanium are used in semiconductors
- enable to surf internet and watch television.
- Semiconductors are used to make diods and transistors.
- Transition elements show different oxidation numbers in their compounds.
- Transition elements form coloured ions or compounds.
- Their compounds are useful catalysts.
Uses In Industries
- Iron is used as a catalysts in the manufacture of ammonia in Haber Process.
- Platinum is used as a catalyst in the Ostwald a process of manufacturing of nitric acid.
- Nickel is used as a catalyst in the manufacture of margerine.
- Vanadium(V) oxide is used as a catalyst in the Contact Process for the manufacturing of sulphuric acid.