lone pairs

[Maldonado3K]

Do lone pairs determine bond angles? In what way? Examples?

[octaviahuang1f]

Lone pairs have greater repulsion than bonded pairs. To form a shape with least repulsion between atoms, the bond angles might become smaller when there's a lone pair than if it's bonded.
Example:
SF4 forms a seesaw shape.
XeF4 has two lone pairs on Xe, so to form the shape with least repulsion, it becomes octahedral. Because the lone pairs repel each other the most, they are on opposite sides of the octahedral. The lone pairs don't have atoms bonded to them, so the actual shape is square planar.

Hope this helps!! :)

[Andrew Evans - 1G]

Yes,
Since lone pairs are considered regions of electron density, they factor in to the shape and arrangement of bonds around an atom. However, as Octavia said, two electrons within one bubble are going to create greater repulsion than just another bonded atom, so a lone pair of electrons are going to push all other bonded atoms a little bit further than your normally expected 109.5º, 120º, ect...


-Andrew Evans
Section 1G

[Adam Yaptangco 1D]

The negative charge of the lone pair electrons repulse other negatively charged electrons in a molecule. This repulsion results in the various bond angles of a molecule.