Inorganic lecture 2

Question 1

State the three quantum numbers that can describe the 3D hydrogen orbital/ atom

Answer 1

n, l and ml

Question 2

Define the lowest energy state

Answer 2

Lowest energy state is the ground state, and has the lowest value of the quantum number

Question 3

State the name given to higher energy states

Answer 3

Excited states

Question 4

Give the equation for wavenumber in which it is split into its radial and angular parts

Answer 4

ᴪ = R(r).Y(𝜃,ɸ)
r = radius
𝜃 (theta) = colatitude/angle defining orientation
ɸ (phi) = azimuth

Question 5

Describe the radial wave function, R(r)

Answer 5

The radial wave function changes with distance from the nucleus - depends only on the radial distance between the nucleus and the electron. It depends on quantum numbers n and l, and contains no information on direction or orientation.

Question 6

Describe the angular wave function, Y(𝜃,ɸ)

Answer 6

The angular wave function changes corresponding to different shapes - depends on direction or orientation but not distance, and on the quantum numbers l and ml. The angles 𝜃 and ɸ define a orientation with respect to a coordinate system.

Question 7

Describe n; the principle quantum number

Answer 7

n describes the size of the orbital and can take any integral value from 1 to ∞. For species with just one electron (eg hydrogen atoms), the energy of the orbital depends on n but not l and ml. For any given n, energy order is s<p></p>

Question 8

Describe l; the angular momentum quantum number

Answer 8

l describes the shape of any orbital. It can take any integral value from 0 to n-1.

Question 9

State which orbital has l=0

Answer 9

s orbital

Question 10

State which orbital has l=1

Answer 10

p orbital

Question 11

State which orbital has l=2

Answer 11

d orbital

Question 12

State which orbital has l=3

Answer 12

f orbital

Question 13

Describe ml, the magnetic quantum number

Answer 13

ml is the orbital orientation quantum number. It can take any integer value from -l to +l. This means there are several different orbitals per value of l

Question 14

State the name given to sets of orbitals with the same value of n

Answer 14

A shell

Question 15

State the name given to sets of orbitals within a shell for which l is the same

Answer 15

A sub shell

Question 16

Define a node

Answer 16

An area of zero electron density

Question 17

State the number of nodes per orbital

Answer 17

n-1

Question 18

State the number of angular nodes per orbital

Answer 18

l

Question 19

State the number of radial nodes per orbital

Answer 19

n - l - 1

Question 20

Describe the change in energy as n increases

Answer 20

As n increases, energy increases.

Question 21

Describe hydrogen orbitals with the same value of n

Answer 21

Eg 2s, 2p both have n = 2, so they have the same energy. In other words, they are degenerate.

Question 22

Describe the value of wavenumber (R(r)) for s orbitals

Answer 22

There is a non zero value of 𝜓 at the nucleus (ie when r = 0) as s orbitals are spherical

Question 23

Describe a radial node

Answer 23

A spherical surface where the sign of 𝜓 changes from positive to negative.

Question 24

Describe the value of wavenumber (R(r)) for p orbitals

Answer 24

𝜓 = 0 at the nucleus (ie when r = 0) as there is a node in the centre of the orbital.