Shapes of molecules

Question 1

What is the shape and bond angle with 2 electron pairs in the outer shell?

Answer 1

linear, 180°

Question 2

What is the shape and bond angle with 3 electron pairs in the outer shell?

Answer 2

trigonal planar, 120°

Question 3

What is the shape and bond angle with 4 electron pairs in the outer shell?

Answer 3

tetrahedral, 109.5°

Question 4

What is the shape and bond angle with 5 electron pairs in the outer shell?

Answer 4

trigonal bipyramidal, 90° and 120°

Question 5

What is the shape and bond angle with 6 electron pairs in the outer shell?

Answer 5

octahedral, 90°

Question 6

Why do lone pairs repel slightly more than bonding pairs?

Answer 6

lone pairs are held closer to the nucleus and are therefore more compact

Question 7

How do you figure out the shape of molecules?

Answer 7

1) figure out which group the central atom is in
2) write down how many atoms are bonded to the central atom
3) add the group number and the bonded atoms together = how many electrons in the outer shell
4) divide electron number from step 3 by 2 to find the number of electron pairs
5) if number of electron pairs = number of bonds then no lone pairs, if it is not equal then that is how many lone pairs there are
6) if no lone pairs then they all repel equally giving a perfect “_____” shape with bonds angle of “_____”
7) if there are lone pairs then they do not all repel equally, giving a shape based on a “_____” with a reduced bond angle of “(a few degrees less than typical)”

Question 8

In trigonal bipyramidal shapes, the lone pairs go…

Answer 8

in the equatorial plane

Question 9

What is the name for water’s shape?

Answer 9

v-shaped/bent