how will i know the no. of valence electrons of an atom.?

Answer 1

Valence electrons of an atom: look at a perodic table group(verticle column in which the elements is cateogorized. The number within the units place identifies how many valence electrons are contained within the elemens listed under the particualr columm.

Click on the URL below for additional information concerning valence electrons

en.wikipedia.org/wiki/Valence_electron

- - - - - - - - - -s-

Answer 2

if theres 1 extra electron, it has one valence
2 s two
3 three
4 four
5 three
6 two
7 one
8 inert.

now it's wrong to say that an atom has 5 or more extra electrons. instead you say it "wants" 1 2 or 3 electrons. this gives the ion a positive charge. cause it wants negative charges. positive wants negative. that's why opposites attract.

also, for the atoms who's outer electron shell is more than 8, i have no idea how to do it.

Answer 3

In chemistry, valence, also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element. Over the last century, the concept of valence evolved into valence bond theory (1927) and then into modern valence bond theory (1990s).

In the link below you will find the Valences of the elements

Answer 4

It depends on what group they are in.

In the main group elements (not the transition metals) it is easy - 1 for the alkali metals and hydrogen, and then add one for each group moving over until you get to the noble gases which is 8. The outer shell is full.
Helium is the exception, being full at 2 in the noble gases.