Quantum

Question 1

Quantum Numbers

Answer 1

Principle Quantum no n (whole no). 2nd quantum no, orbital quantum no l ((0-(n-1), 3rd quantum no magnetic quantum no m (values between -l and +l. l value of 2nd quantum no)

Question 2

Quantum Spin, 4th quantum no

Answer 2

In addition to charge, each electron has a small magnetic field around it, as though it contains a tiny bar magnet. This magnetic property of electrons is known as spin. The ‘magnet’ can point in one of two directions, and doubles the total number of quantum states: a set of standing waves can be formed with spin pointing in one direction, and another set formed with the spin pointing in the other direction.
ms(small s) +1/2 or -1/2

Question 3

Quantum no rule regarding no of states

Answer 3

(4l+2) quantum states for each value of l

Question 4

electronvolt (eV)

Answer 4

1.602 x 10^-19J. eV to J, multiply eV by 1.602 x 10^-19 JeV^-1. 1 eV is the energy gained by an electron moving through a potential diff of 1v

Question 5

Photon energy

Answer 5

E=hf (h planck’s constant, f frequency). Also applied to energy of electron waves

Question 6

Electron states

Answer 6

Ground , Excited. Lower energy closer to nucleus

Question 7

Shell, subshell, orbital

Answer 7

s subshell 2 electrons / quantum states
p subshell 6 electrons / quantum states
d subshell 10 electrons / quantum states
f subshell 14 electrons / quantum states
Shell has principal quantum no, hold up to max of 32 electrons in 4th shell. No of electrons in Nth shell is 2(n^2).  Subshell within a shell, angular momentum quantum no. Orbital describes wave like behaviour of an electron, magnetic quantum no, max of 2 electrons. 

Eg: The third shell has 3 subshells: the s subshell, which has 1 orbital with 2 electrons, the p subshell, which has 3 orbitals with 6 electrons, and the d subshell, which has 5 orbitals with 10 electrons, for a total of 9 orbitals and 18 electrons

Question 8

Energy level of hydrogen like ion (single electron)

Answer 8

Orbitals scaled down by factor of Z (Z is atomic no so no of protons). Apart from that same shape and quantum nos as hydrogen orbitals.
-(Z^2 x 13.6eV)/n^2. Normal equation for hydrogen energy: (-13.6eV)/n^2
With hydrogen only, energy of each state depends on just n number. Eg 2s and 2p states have same energy

Question 9

Energy level in ion lower than in hydrogen atom so tronger binding between electron and nucleus means…

Answer 9

lower energy for quantum state

Question 10

Orbital letters

Answer 10

Taken from l (orbital quantum no) s, p, d,f for l=0,1,2,3
Write n and letter representing l next to each other, so 2p is n=2,l=1 . 4s is n=4,l=0
NB 2s could refer to 2 possible quantum states so all nos needed to describe that.
First 3 quantum nos needed to identify orbitals uniquely
So cannot refer to specific orbitals or quantum states with just 2s

Question 11

Every electron has its own set of quantum nos, so if 2 electrons, 8 quantum nos need, 5 electrons 20 quantum numbers are needed so…

Answer 11

No of electrons x 4 = no of quantum numbers needed to describe quantum states

Question 12

1s is Quantum state of electron

Answer 12

NOT of whole atom. But 1s 1s indicates state of atom with 2 bound electrons. Or 1s^2 (^2 not a power just saying orbital doubly occupied).

Question 13

Notation

Answer 13

eg 1s2s. Eg ground state of lithium (3 electrons) 1s^2 2s

Boron ground state electron configuration is 1s^2 2S^2 2p

Question 14

Pauli exclusion principle

Answer 14

The Pauli exclusion principle bans any two electrons from having the same quantum state.

Question 15

Screening

Answer 15

Negative charge from 1s electrons cancels out some of the positive charge from nucleus

Question 16

Ground state energy

Answer 16

Lowest energy as nearer nucleus so some of pos charge cancelled by negative charge. Ground state is lowest energy

Question 17

Orbital filling order

Answer 17

s,p,d,f. Order can be hard to predict though as orbital energies vary between different atoms. So Madelung rule helps

Question 18

Madelung rule

Answer 18

The Madelung rule predicts that the ground state of an atom is formed by completely filling orbitals in the order of the sum of the principal and orbital quantum numbers n+l, For orbitals where n+l is the same, then orbitals fill in order of increasing n.
Remember n+l, l number: S=0,p=1,d=2,f=3