Covalent + Ionic bonding ..

jcf

Hi
Question about Covalent Bonding.

1st off with Ionic bonding - take NaCl

Sodium (Na) has one electron in it's outer shell - Cl has 7 - so Na needs to lose one to have a stable outer shell and Cl needs one.

Na loses one and becomes Na+ (more protons => +) , Cl gains this one and becomes - (more elections => -)

So they pair up as +- attract - I think this is correct so far?


So with Covalent Bonding take H20 - The Hydrogen atoms have 2e's in their shell - stable as they bond with O - so they share e's , but is the H negatively charged ?

thecornflake

jcf wrote: »

Hi
Question about Covalent Bonding.

1st off with Ionic bonding - take NaCl

Sodium (Na) has one electron in it's outer shell - Cl has 7 - so Na needs to lose one to have a stable outer shell and Cl needs one.

Na loses one and becomes Na+ (more protons => +) , Cl gains this one and becomes - (more elections => -)

So they pair up as +- attract - I think this is correct so far?


So with Covalent Bonding take H20 - The Hydrogen atoms have 2e's in their shell - stable as they bond with O - so they share e's , but is the H negatively charged ?

The H is ever so slightly positive resulting in a dipole. The following explanation is wrong but, imagine the electron revolving around the H proton. Now, bring it close to the oxygen and it revolves around the oxygen atom and hydrogen atom in a figure 8 shape. The oxygen atom is more "hungry" for the electron so the electron spends most of its time circling the oxygen than the hydrogen. Thus the electron is shared between the two atoms as opposed to being on just one atom.

I must stress however that the above is just for a visual aid, it is not what actually happens. To describe it fully you have to use QM wavefunctions.

jcf

Indeed thanks, but this is how I remember doing it in school.

So the H has still 1e in it's shell that it shares with the O ?

and with both H, the O gets 2 extra e's in it's outer shell to give it a stable shell ?

But now the H has an unstable outer shell??


weird ... I wish I was back at school when I was clever :mad:

Agent_99

The Hydrogen and Oxygen "share" the electrons. H fills it's 1S valance shell by having 2 electrons shared with Oxygen and Oxygen completes it's shell by sharing with 1 electron from the two H creating a stable compound.

Parsley

they're shared. imagine the two electrons, one from oxygen and one from hydrogen in the middle, between the two atoms, moving around in a space which makes the covalent bond.

http://en.wikipedia.org/wiki/Covalent_bond