Atomic Structure Flashcards
What does TOF mass spectrometry detect?
The mass and relative abundances of isotopes in 3 stages
What are the 3 stages of TOF mass spectrometry?
1 - Ionisation2- Acceleration3- Detection
How is ionisation carried out in TOF mass spectrometry?
- By electron Impact- Sample is vaporised- Electrons are fired with an electron gun at the vaporised sample- An electron is knocked off to give 2 e-‘s and a positively charged ion
How is acceleration carried out in TOF mass spectrometry?
- Positively charged ions approach two charged plates that have an electrical field- Ions are accelerated forward with the same kinetic energy - Ions will have different velocities depending on their mass- Ion drift
How is detection carried out in TOF mass spectrometry?
- Negatively charged detector- As ions hit the detector they gain an e- causing an electrical current- current is detected, monitored and analysed to give a spectra
What does mass spectra show?
The relative abundances of different isotopes present and their masses
What is m/z?
The mass to charge ratio
What are the units of kinetic energy?
Joules
What are the units of mass?
Kg
What are the units of velocity?
Metres per second
What are the units of distance?
Metres
What are the units of time?
Seconds
How do you work out the mass of one ion?
Divide the Ar by Avogadros constant
How do you work out kinetic energy?
Half the mass times the velocity squared
How do you calculate velocity?
The square root of 2 x kinetic energy divided by mass
What shape are S orbitals?
Spherical
How many S orbitals are found together?
1
How many electrons do S orbitals hold altogether?
2
How many electrons can 1 S orbital hold?
2
What shape are P orbitals?
Figure of 8
How many P orbitals are found together?
3
How many electrons do P orbitals hold altogether?
6
How many electrons can 1 P orbital hold?
2
What shape are D orbitals?
Various
How many D orbitals are found together?
5
How many electrons do D orbitals hold altogether?
10
How many electrons can 1 D orbital hold?
2
In energy level 1 what are the orbitals?
One S
In energy level 1 how many electrons are found?
2
In energy level 1 What is the notation?
1s
In energy level 2 what are the orbitals?
One S and three P
In energy level 2 how many electrons are found?
8
In energy level 2 what is the notation?
2s2p
In energy level 3 what are the orbitals?
One S, three P and five D
In energy level 3 how many electrons are found?
18
In energy level 3 what is the notation?
3s3p3d
In energy level 4 what are the orbitals?
One S, three P and five D
In energy level 4 how many electrons are found?
18
In energy level 4 what is the notation?
4s4p4d
What do ‘electrons in boxes’ show?
Electron pairing and spin
What is Hunds rule?
Electrons occupy empty orbitals before pairing to minimise repulsion
Why does the notation change for ions?
To account for the loss/gain of electrons
Which electrons are affected?
Outer electrons only
What does isoelectronic mean?
Same electronic structure
What is the rule for transition metals?
4s in before 3d and 4s out before 3d
What is the 1st molar ionisation energy?
The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms (kj.mol^-1)
What is the 1st molar ionisation energy equation?
X(g) -> X^+ (g) + e^-
What does the 1st molar ionisation energy depend on?
- Nuclear Charge- Sheilding- Distance
How does nuclear charge effect I.E.?
As nuclear charge increases so does I.E.
How does sheilding effect I.E.?
As sheilding increases, I.E. decreases
How does distance effect I.E.?
As distance increases, I.E. decreases
How does molar I.E. change down a group?
Decreases
How does nuclear charge change down a group?
Increases
How does sheilding change down a group?
Increases
How does distance of e^- to nucleus change going down a group?
Increases
What effect do an increase in sheilding and distance have?
they lower the effective charge on the nucleus which decreases the attraction between the nucleus and the outer e^-
How does I.E. change across a period?
Increases
How does nuclear charge change across a period?
Increases
How does distance change across a period?
No change
How does sheilding change across a period?
No change
How does attraction between outer electron and the nucleus change?
Increases
How does energy needed change?
Increases
Why is there an exception between groups 2 and 3?
3 is easier to remove than 2 because of sheilding from the full s orbital
Why is there an exception between groups 5 and 6?
6 is easier to remove than 5 because of electron repulsion between paired electrons
What is a successive I.E.?
The energy required to remove electrons one by one from the same atom
Define the second ionisation energy?
The energy required to remove 1 mole of electrons from one mole of gaseous 1+ ions
What is the second ionisation energy equation?
X+ (g) -> X^2+ (g) + e^-
What is the general trend in successive I.E.s?
Increase in I.E. because of increasing effective charge on the nucleus because of decreased sheilding, decreased distance and therefore stronger nuclear attraction
What are the large jumps caused by?
Moving from an outer energy shell inwards
What does the notation detail?
The positions of the electrons in their respective energy levels and orbitals
What does the big number represent?
The energy level
What does the letter represent?
The orbital type
What does the superscript represent?
Number of electrons in the orbital
