How to make a strong electromagnect which can lift about 1kg...
Could u plz help me with this? ....

 

What materials do you have to work with? To start you will need some round bar stock, some insulated wire, a switch, and a DC voltage source.

Then check out this calculator
http://www.daycounter.com/Calculators/Magnets/Solenoid-Force-Calculator.phtml

 

AC current can be used and you can pick up ferrous metals and also aluminum and copper due to eddy current inductive effects.

2.2 pounds is not much mass. You should he able to stay well below 10 amps of current.

Heat build up will be your biggest concern

 

Lifting type electromagnets usually have the metal core in a "pot" or "radial" configuration, although for a DIY magnet a "U" would be easier to make. They are made in this style to have both poles in use. A straight or bar type will only have one of the poles usable. A link to a company making lifting magnets showing a "pot" or linear type - http://www.magnetechcorp.com/round.html

 

Also for maximum attraction you need the attracting surface completely flat and also it is an advantage to have the same on the material being lifted.
You may need a reverse polarity pulse to release small lighter items due to residual, as is done with scrap cranes etc.
Max.