I am having our exam on next day.Pls tell me a trick to study the valencies of elements.?
The position of the elements in the periodic table gives you clues about the valences of each element. Also, if you remember the formulae for familiar substances (like carbon dioxide, water, sulfur dioxide, hydrochloric acid, etc) that will also give you clues about possible or likely valences. \n\nThe final answer is:\n\nmemorize.
Different people have different ways of memorizing best.  Some people learn best from listening and speaking.  Some people learn best from reading or looking.  Some people learn best from moving, and so on.  Here are some ideas:\nWrite out all the words and their definitions in sentences.\nMake up a dance or a song for each word.\nDraw a colorful chart.\nUse flashcards.\nRecord a tape of yourself saying the words and then listen to the tape repeatedly.