quantum mechanics

Question 1

what is the rydberg equation?

Answer 1

v(frequency) = Rh [1/n (initial) ^2 - 1/n (final)^2 ]

Question 2

what is the rydeberg equation used for?

Answer 2

to calculate the frequency of light when an electron moves form one orbital to another.

Question 3

what does n (initial) equal in the Balmer series

Answer 3

2

Question 4

what does n (initial) equal in the Paschen series

Answer 4

3

Question 5

what does n (initial) equal in the Lyman series

Answer 5

1

Question 6

what type of light is used for the Lyman series

Answer 6

ultra violet

Question 7

what type of light is used for the Balmer series

Answer 7

visible

Question 8

what type of light is used for the paschen series

Answer 8

infrared

Question 9

what happens if you are able to fully remove an electron from an atom (move it up an infinite number of shells.)

Answer 9

the n (final) becomes infinity, any number over infinity is 0. (this is the same thing as ionisation energy.)

Question 10

when the Rydberg equation to calculate the ionisation energy, the infinity should go _____ and the second value should be ______

Answer 10

first, stated in the question

Question 11

what is the de Broglie equation?

Answer 11

wavelength = h/mv (velocity)

Question 12

when would you use the de Broglie equation ?

Answer 12

when calculating the wavelength of a moving object

Question 13

what does the Heisenberg uncertainty principle state ?

Answer 13

it is impossible to predict both the precise position and momentum of an object. - the more precise that we know the of the location, the more uncertain the momentum will become and vice versa.

Question 14

what is the equation for the Heisenberg uncertainty principle?

Answer 14

delta p . delta q >= h/4pi

Question 15

how do you calculate the change in momentum ?

Answer 15

since p=mv
delta = m . deltav

Question 16

what element is the schrodinger equation used for and why?

Answer 16

hydrogen, as it only has 1 electron.

Question 17

what does H^ stand for and what does it hold?

Answer 17

the Hamiltonian operator, and it holds all the info on the conditions of the atom.

Question 18

what is the Schrödinger equation

Answer 18

H^ Y(wave function symbol) = E Y( wave function symbol)

Question 19

what is the equation (linked to the Schrödinger equation), which helps us find the energy for the different hydrogen orbitals?

Answer 19

En = - hR/n^2

Question 20

what is an orbital?

Answer 20

an orbital is the region of space defined by the wave function

Question 21

what does the radial wavefuntion describe ? [R(r)]

Answer 21

the distance of an electron from the nucleus of an atom

Question 22

what does R(r)^2 stand for

Answer 22

the radial probability density

Question 23

what does the radial probability density show us ? [R(r)^2]

Answer 23

The probability of finding the electron at a point located distance r from the proton.

(This is important to use as a square number can never be negative. )

Question 24

what is the equation for the radial distribution function?

Answer 24

4pi(r)^2R(r)^2

Question 25

draw the graph of R(r) for a 1s orbital

Answer 25

exponential decay from 1

Question 26

draw the graph of R(r) for a 2s orbital

Answer 26

exponential decay from 1 and a dip below the x axis.

Question 27

draw the graph of R(r) for a 2p orbital

Answer 27

starting from 0 straight up to 1, then an exponential decay back to 0.

Question 28

draw the graph of R(r) for a 3s orbital

Answer 28

exponential decay from, a dip below the x axis and a hump above the x axis.

Question 29

draw the graph of R(r) for a 3p orbital

Answer 29

starting from 0 straight up to 1, then an exponential decay back to 0, with an dip below the x axis

Question 30

draw the graph of R(r) for a 3d orbital

Answer 30

same as 2p, but a less steep line up to 1 from the origin.

Question 31

what do the graphs look like for R(r)^2

Answer 31

in tetxbook - s starts from 1 never drops below 0

Question 32

draw the graphs for the radial distribution function against r

Answer 32

in textbook - all start from origin - extra waves are smaller before the big wave - never drops below 0

Question 33

when does a node exist?

Answer 33

where there is a 0% chance of finding an electron. where R(r)=0

Question 34

what helps you determine the number of radial nodes?

Answer 34

n - l - 1 = number of radial nodes

Question 35

where there is no nodes there is ....

Answer 35

0 probability of finding an electron

Question 36

what helps you determine the number of angular nodes?

Answer 36

It is equal to the value of l

Question 37

draw the d xy orbital

Answer 37

in between the x and y axis

Question 38

draw the d yz orbital

Answer 38

in between the z and y axis

Question 39

draw the d xz orbital

Answer 39

inbetween the x and z axis

Question 40

draw the x^2 - y^2 orbital

Answer 40

lies on the x and y axis

Question 41

draw the z^2 orbital

Answer 41

p orbital along the z axis and a ring around the centre

Question 42

what is the Pauli exclusion principle

Answer 42

No 2 electrons in the same atom can have the same 4 quantum numbers.

Question 43

what is aufbaus principle

Answer 43

orbitals much be filled in order of increasing energy

Question 44

what is hunds rule

Answer 44

When filling a set of degenerate orbitals, electrons are added with parallel spins to different orbitals.

Question 45

for what elements is hunds rule broken

Answer 45

chromium and copper

Question 46

what is the order of better shielding

Answer 46

s>p>d>f

Question 47

how do you find the total nuclear charge on a nucleus

Answer 47

the number of protons

Question 48

draw a 3p orbital

Question 49

draw a Pz orbital

Answer 49

only side on one

Question 50

strong s-p mixing occurs when s and p have ____

Answer 50

similar energies - elements bonding up to carbon is normally considered to have strong s-p mixing

Question 51

why are 2s orbitals more penetrating than 2p orbitals?

Answer 51

(higher probability of finding an electron.) The presence of the radial node of the 2s orbital mean sit has an area of high electron density close to the nucleus, which the 2p doesn't. The 2s electron is said to penetrate the 1s electron and thus the 2s electron feels higher effective nuclear charge than the 2p electron. The 2s orbital is therefore more stabilised than the 2p orbital.

Question 52

what does u mean

Answer 52

when the orbital is inverted it experiences a phase change.