L2 - Orbital Theory, E- Configuration And Hybridisation

Question 1

What are cathode rays?

Answer 1

electrons that are moving through space

Question 2

what are electrons?

Answer 2

wavefunctions

behave as a particle and a wave

Question 3

what do wavefunctions give a possibility of?

Answer 3

finding an electron at any given location round the nucleus

Question 4

what are atomic orbitals?

Answer 4

• the pattern of probabilities of positions of electrons around the nucleus
• depending on its energy level, it exists in certain regions around the nucleus

Question 5

what are the 4 types of atomic orbitals?

Answer 5

s
p
d
f

Question 6

how does filling shells work?

Answer 6

• electrons fill the lowest energy shells first
• form pairs

Question 7

what are s orbitals?

Answer 7

orbitals that are spherical
- centred on the nucleus
- have the highest probability of finding the electron at the nucleus

Question 8

what are p orbitals?

Answer 8

orbitals that are 2 ellipsoids
- have a point of tangency at the nucleus
- no probability of finding an electron at the nucleus

Question 9

what are d orbitals?

Answer 9

orbitals that are 3 pear-shaped lobes
- they are all in one plane

Question 10

what is the valency of an atom?

Answer 10

the number of bonds needed to complete the shell

Question 11

what is orbital hybridisation?

Answer 11

mixing up the atomic orbitals to give new molecular orbitals?

Question 12

how is orbital hybridisation achieved?

Answer 12

with an energy input
to promote electrons within the atomic orbital shells

Question 13

what is sp3?

Answer 13

tetrahedral (109.5)
- s-orbital and all 3 p-orbitals

Question 14

what is sp2?

Answer 14

trigonal planar (120)
- s-orbital and 2 p-orbitals

Question 15

what is sp?

Answer 15

linear (180)
- s-orbital and p-orbitals

Question 16

what is a sigma bond?

Answer 16

single bond
- strongest type of covalent chemical bond
- form when atomic orbitals overlap in a head on arrangement

Question 17

what can sigma bonds be formed from?

Answer 17

• s-orbital and p-orbital = σs-p
• s-orbital and sp-orbital = σs-sp hybrid
• the lobe of the orbital opposite is involved in a substitution reactions

Question 18

what are pi bonds?

Answer 18

• covalent bonds formed from overlap of 2 orbital lobes on one atom with 2 of another in a lateral sense
• there is a plane between the molecular orbitals with no electron density

Question 19

what are lone pairs?

Answer 19

paired electrons occupying one or more of the hybridised orbitals

Question 20

what is the influence of lone pairs?

Answer 20

lone pairs are held closer to the atom than bonding electrons
exert more repulsion on other valence electrons
= compressed bonding angles

Question 21

what rotation do sigma and pi bonds have and what does this cause?

Answer 21

sigma bonds - free rotation
pi bonds - fixed rotation
= leads to isomers (stereochemistry)