in chemistry,like how do u get the valency?eg..oxygen{o2},hydrogen{h2}?

Question

i know what exactly are the name's given,but i need to know how can i learn the numbers given biheart!
people please understand my problem and help me!!!!!!!!

Answer 1

In the periodic table the group no tells the valency of all the elements in that group.
If u draw each element with all the electrons in the shells , the last shell is the valence shell and and the electrons in it are called valence electrons.
Oxygen is in 6th group so it has 6 electrons in its valence shell and hence has to gain 2 electons to become stable ( octet configuration) 2, 6

Magnesium12 - electron configuration : 2, 8 ,2
The last shell has 2 electrons and has to lose these 2 electrons to gain octet configuration.

You cannot byheart valency, but u can byheart atomic no and hence u can find the valence electrons.

I hope u got it.

Answer 2

by knowing the atomic number and the no of valence electrons. eg chlorine has 7 valence electrons hence it accepts 1 elecron to attain octet arrangement
an easier way is from H2O (water) we can infer the valencies of hydrogen and oxygen .
the valency of oxygen is 2 and that of hydrogen is 1 (2 comes after H so thats the valency of oxygen
theres no number after O so hydrogens valency is 1
another compound HCl valency of H and Cl is 1

from NH3 we infer the valency of N=3 and H=1

Answer 3

it's very easy. u just need to remember da atomic no. n dats also very easy. den arrange da electrons in the respective shells K, L, M, N. K shell can accomodate 2 electrons, L-8, M-18, N-32. And the no. of electrons in da outermost shell cannot be more than 8. Atomic no. of oxygen =8 ,therefore its configuration is K-2, L-6 so da valency is either the no. of electrons in da outermost shell if it is below 4 or 8 minus da no. of electrons in the outermost shell if it is above 4. so oxygens valency will be 8-6=2

Answer 4

no the atomic number of the element
Ex:- calcium atomic NO.=19
there are shells for distribution of atoms
first shell(K)contains maximum
from second all the cells can contain a maximum of 8 shells
second shell L third shell M and so on
electronic configuration of calcium is 2,8,8,1
valency is NO.os atoms present in the last shell.
therefore valency of calcium is 1
EX2:-titaniumatomic no=25
electronic configuration first shell 2 and second shell 8 and third 8 and fourth 8 and fifth shell 4
therefore the valency of titanium is 6.

Answer 5

the number of electrons present in the outer most shell of an atom tells the valeny .