## How to know which angles are smaller

(Polar molecules, Non-polar molecules, etc.)

zfinn
Posts: 106
Joined: Fri Aug 30, 2019 12:16 am

### How to know which angles are smaller

in a VSEPR shape with more than one angle size, i.e. seesaw, would all the angles decrease because of the lone pair (so angles are <90, <120, <180)? or do just the angles next to the lone pair bonding region decrease?

Montana James 4G
Posts: 46
Joined: Wed Sep 18, 2019 12:21 am

### Re: How to know which angles are smaller

The lone pair pushes the other regions of electron density closer to each other, making the bond angles smaller. but we can only do this qualitatively, we don't know exactly how much they change.

Leila_4G
Posts: 114
Joined: Sat Sep 14, 2019 12:17 am

### Re: How to know which angles are smaller

What are the angles of the AX2E VSEPR formula? I think this is either a bent shape or trigonal planar but I'm not sure

Leila_4G
Posts: 114
Joined: Sat Sep 14, 2019 12:17 am

### Re: How to know which angles are smaller

Also, what are the angles of AX5E (which I think is a square pyramidal shape)?

Dakota Walker 1L
Posts: 58
Joined: Wed Sep 18, 2019 12:17 am

### Re: How to know which angles are smaller

Square pyramidal shapes have slightly less than 90 degree angles.

Kishan Shah 2G
Posts: 132
Joined: Thu Jul 11, 2019 12:15 am

### Re: How to know which angles are smaller

@Leila: The shape of AX2E is bent. The bond angles are 120 degrees. For AX2E2 it is still bent, but the bond angles are 109.5 degrees since the two lone pairs push the two atoms further away from them therefore decreasing the angle.

Bita Ghanei 1F
Posts: 60
Joined: Thu Feb 28, 2019 12:15 am

### Re: How to know which angles are smaller

For seesaw, it would just be <90 and <120
for T-shaped, it would only be <90

Sam McNeill 1E
Posts: 110
Joined: Sat Aug 24, 2019 12:17 am

### Re: How to know which angles are smaller

Just remember that anything with a lone pair has less than angles of the original parent electron configuration.

Posts: 58
Joined: Thu Jul 25, 2019 12:15 am

### Re: How to know which angles are smaller

Leila_4E wrote:Also, what are the angles of AX5E (which I think is a square pyramidal shape)?

the bond angles of an octahedral are 90. Therefore, as there is a lone pair in AX5E, the shape is a square pyramidal and the resulting bond angles are <90