Lecture 10 - Molecular Shape

Question 1

what makes up covalent bonds?

Answer 1

2 nonmetals or a nonmetal + metalloid

Question 2

what is special about metals?

Answer 2

they don’t combine, instead mix into alloys

Question 3

atoms with 1, 2 or 3 valence electrons form…

Answer 3

1, 2, or 3 bonds

Question 4

atoms with 4 or more valence electrons form…

Answer 4

enough bonds to make an octet

Question 5

why is boron an exception to the octet rule?

Answer 5

it only wants 6 valence electrons, only taking on 3 bonds

Question 6

why are elements in group 3A exceptions to the octet rule?

Answer 6

they do not have enough valence electrons to form octets in natural molecules.

Question 7

what is VSEPR?

Answer 7

Valence Shell Electron Pair Repulsion. molecules are most stable when its lone pairs and bonds are as FAR from each other as possible

Question 8

what is a linear lewis dot shape?

Answer 8

any atom surrounded by only 2 groups, bond angle of 180 degrees (AX2)

Question 9

what is a trigonal planar lewis dot shape?

Answer 9

any atom surrounded by 3 groups, bond angles of 120 degrees (AX3)

Question 10

what is a tetrahedral lewis dot shape?

Answer 10

any atom surrounded by 4 groups, bond angles of 109.5 degrees (AX4)

Question 11

what is a trigonal pyramid lewis dot shape?

Answer 11

if the 4 groups around an atom include 1 lone pair, bond angles of ~109.5 degrees (AX2E)

Question 12

what is a bent lewis dot shape?

Answer 12

if the 4 groups around the atom include 2 lone pairs, bond angle is 105 degrees (AX2E2)

Question 13

when drawing lewis structures for polyatomic ions…

Answer 13

add one electron for each negative charge, subtract one electron for each positive charge

Question 14

what are resonant structures?

Answer 14

2 lewis structures with the same atoms but different arrangements of electrons