[Destiny]

When Ammonia reacts with H+, NH4+ is formed and there is a formation of a dative bond.
But i dont understand how N gets a +1 charge in NH4+ ion 

[Hunter2]

What happen if you add to a neutral molecule a positive charge.

Ammonia is neutral. The hydronium ion is positive charged.

[fledarmus]

Formally, the electrons in the bonds between N and H are assumed to be equally shared. This means that each H atom will have one electron, and since they have an atomic number of 1 (1 proton), they are neutral. The N atom has four electrons (one for each bond), and since it has an atomic number of 5, it has five protons and only four electrons, giving it an excess positive charge - +1

[Destiny]

I didnt understand that N has 4 electrons (one for each bond)
2 electrons are required to form one bond right? 

[fledarmus]

I didnt understand that N has 4 electrons (one for each bond)
2 electrons are required to form one bond right? 

Yes, but when you are counting for formal charges rather than for the octet rule, you pretend that each atom in a covalent bond gets half of the electrons in the bond.

[Destiny]

so we get this with the help of lewis structure ?

[Destiny]

K, so i have got the answer now and thnx for helping me