bonds and molecules

Question 1

what is a dative bond

Answer 1

a covalent bond where both the electrons come from the same atom.

Question 2

what is the bond dissociation enthalpy

Answer 2

a measure of the bond strength.
- the standard enthalpy change for the reaction in which the bond in question is broken

Question 3

what is the molecular orbital theory

Answer 3

the idea that atomic orbitals combine to form molecular orbitals that are spread over the whole molecule.

Question 4

what does the number at the start tell us ?

Answer 4

the energy of the orbital in the molecule. 1 being the lowest

Question 5

what does sigma mean

Answer 5

a end on overlap

Question 6

what does pi mean

Answer 6

a side on overlap

Question 7

g and u are called _____ labels

Answer 7

parity

Question 8

if the orbital looks identical after inversion it is a …

Answer 8

g type

Question 9

if the orbital has the same shape but changes phase after inversion it is a …

Answer 9

u type

Question 10

bonding s orbitals have ____ electron density

Answer 10

increased

Question 11

antibonding s orbitals have ____ electron density

Answer 11

decreased

Question 12

bonding orbitals _____ energy to the surroundings

Answer 12

release

Question 13

anti bonding orbitals ____ energy from the surroundings

Answer 13

require

Question 14

how do we calculate the bond order

Answer 14

= number of filled bonding orbitals - number of filled anti bonding orbitals

Question 15

the higher the bond order the _____ stable the atom

Answer 15

more

Question 16

the higher the bond order the ______ the bond length

Answer 16

shorter

Question 17

how can you find out If the molecule doesn’t exist

Answer 17

if the bond order was to equal 0

Question 18

how can you tell if you gain stability using a MO diagram

Answer 18

if the energy of the molecule is less than the energy of the separate atoms

Question 19

the pi overlap is ____ than the sigma overlap

Answer 19

weaker

Question 20

paramagnetic is when ____

Answer 20

there is a partially filled energy level

Question 21

isoelectronic species have ….

Answer 21

the same number of electrons

Question 22

what does paramagnetic mean

Answer 22

when the molecule is attracted to magnetic surface

Question 23

what does diamagnetic mean

Answer 23

when a molecule is repelled by a magnetic surface

Question 24

what causes s-p mixing?

Answer 24

the interactions between sigma orbitals derived from s and p atomic orbitals

Question 25

what becomes destabilised during s-p mixing ?

Answer 25

the 3 sigma g and 3 sigma u*

Question 26

pi orbitals are not affected by s-p mixing as …

Answer 26

they are the wrong symmetry to interact with the sigma s orbitals