Charles CollingwoodChemistry and Integrated Science Teacher

The Lewis structure of water

Name: The Lewis structure of water
Uploaded: 2012-04-08T15:09:59+00:00
Duration: 1 min 26 s
Channel: Charles Collingwood
Description: A short spoken explanation of the Lewis structure and geometry of water (H2O) by Charles Collingwood. The speaker states oxygen (group 6) has six valence…

8 Apr 2012 · 1 min

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1:26

A short spoken explanation of the Lewis structure and geometry of water (H2O) by Charles Collingwood. The speaker states oxygen (group 6) has six valence electrons, forms two single bonds with hydrogen using two electrons, leaving two lone pairs on oxygen. Electron pairs arrange tetrahedrally (electronic shape) while the molecular shape is bent/Angular because only two bonding pairs hold hydrogens. Lone-pair–bonding-pair repulsion reduces the H–O–H bond angle from the tetrahedral 109.5° to about 104.5°.

Questions this video answers

H2O

Six (oxygen is in group 6).

Two lone pairs (four electrons).

Tetrahedral (electron pairs arrange tetrahedrally).

Angular (bent).

Chapters

The Lewis structure of water. Water has the formula H2O. So we start off with oxygen. Oxygen is in group six, so it has six electrons in the outer shell. It's bonded to two hydrogens, one, two. And these two bonds are by shared pairs of electrons. Now oxygen in group six then starts off with six electrons in the outer shell. It's used two and so it has four more electrons, two lone pairs. Now this means that tetrahedrally, so the electron pairs arrange themselves as far apart as possible, which is tetrahedral. This is the electronic shape tetrahedral. And two pairs of electrons are holding the hydrogens. So the molecular shape is angular or bent. Incidentally, the repulsion experienced by the bonding pairs from the lone pairs is greater than the experience of the bonding pairs for each other. And so the bond angle closes down ever so slightly. So Instead of being 109 and a half degrees, it's about 104 and a half degrees.