PERIODIC TABLE OF ELEMENTS

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

Uses Of Group 18 Elements

• 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

GROUP 17

Physical properties

• poor conductor of heat # poor electric conductor
• low melting & boiling points # called as halogen (salt former).

1. Fluorine # pale yellow gas
2. Chlorine # greenish-yellow gas
3. Bromine # reddish-brown liquid
4. 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

• 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.