4
Two. One hydrogen atom has one valence electron, so two hydrogen atoms will have two valence electrons :)
Hydrogen has 1 valence electron, whereas helium has 2 valence electrons.
Silicone has 4 valence electros so it would need 4 hydrogen atoms to give itself an octet of valence electrons.
Through covalent bonding, the nitrogen atom will have 8 valence electrons, the hydrogen atoms will each have 2 valence electrons, and the chlorine atom will have 8 valence electrons.
H2 is not an atom, it is a diatomic molecule. Each hydrogen atom has 1 valence electron. When two hydrogen atoms covalently bond to form an H2 molecule, there are two valence electrons being shared by the two atoms.
covalent
Hydrogen atoms have one valence electron which is also the only electron they have.
all carbon atoms have 4 valence electrons. 4 hydrogen atoms can bond to a single carbon. That would be methane.
valence electrons
Hydrogen has 1 valence electron. Bromine has 7 valence electrons. When hydrogen and bromine react, the bromine atom 'steals' the hydrogen atom's only electron. The hydrogen atom then has no electrons and the bromine atom has 8 valence electrons. The two atoms are now ions because their number of protons does not equal their number of electrons. The bromine atom is now a bromide anion and the hydrogen atom is now a hydrogen cation (a proton). The two ions remain together, ionicly bonded and together are called hydrogen bromide.
An unbonded oxygen atom has eight electrons, with six of the electrons located in the valence shell. Two of the valence electrons are unpaired, and therefore can undergo covalent bonding with other oxygen atoms or nonmetals (such as hydrogen).
Non-metal atoms form covalent bonds in which their unpaired valence electrons are shared between the atoms. This sharing has the overall effect of giving both atoms an octet of valence electrons, or two valence electrons in the case of hydrogen.