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53 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What’s atomic number |
Number of protons in an atom of an element |
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What is mass number |
Sum of mass of proton and neutrons in an atom of an element |
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What are isotopes |
Atoms of the same element with different number of neutrons |
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What’s relative atomic mass |
The mean mass of an atom of an element compared to 1/12th of the mass of C-12 |
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What are the four stages in time of flight mass spectrometry |
1) Ionisation 2) Acceleration 3) Ion Drift 4) Detection |
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What Ionisation method is used for: 1- small particles (elements or low Mr compounds/molecules) 2- larger molecules or compounds with higher Mr |
1- Electron impact Ionisation 2- Electro Spray Ionisation |
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What Ionisation method is used for: 1- small particles (elements or low Mr compounds/molecules) 2- larger molecules or compounds with higher Mr |
1- Electron impact Ionisation 2- Electro Spray Ionisation |
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How are samples accelerated in time of flight mass spectrometry |
Samples have +1 positive charge They’re accelerated by a negative electric field to reach a detector They all have same kinetic energy But lighter particles will travel faster and heavier ones slower |
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What Ionisation method is used for: 1- small particles (elements or low Mr compounds/molecules) 2- larger molecules or compounds with higher Mr |
1- Electron impact Ionisation 2- Electro Spray Ionisation |
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How are samples accelerated in time of flight mass spectrometry |
Samples have +1 positive charge They’re accelerated by a negative electric field to reach a detector They all have same kinetic energy But lighter particles will travel faster and heavier ones slower |
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How is a final graph reached in time of flight mass spectrometry |
Lighter ions reach detector first Positive ions gain an electron at the negatively charged plate and turn into ions This generates a current - the greater the current is at that split second the greater the peak on the graph (ie the abundance of that species) |
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How does electron impact ionisation take place |
- sample is vaporized to become gaseous - a hot wire filament acts as an electron gun and shoots electrons at the sample - high energy electrons knock off an electron from the particle in the sample - particle in sample now has +1 charge |
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How does electron impact ionisation take place |
- sample is vaporized to become gaseous - a hot wire filament acts as an electron gun and shoots electrons at the sample - high energy electrons knock off an electron from the particle in the sample - particle in sample now has +1 charge |
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Equation for sodium undergoing electron impact Ionisation |
Na (g) + e- > Na+ (g) + 2e- |
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Advantage of electron impact Ionisation |
It’s simple Highly efficient Highly sensitive |
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Disadvantage of electron impact ionization |
Small compounds can be easily fragmented |
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How does electron Spray Ionisation take place |
- sample dissolved in volatile solvent - then injected through a needle with positive charge at the end - as sample goes through needle it picks up a proton on its way out - the positively charged substance in the sample leave as a fine midst to be accelerated |
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How does electron Spray Ionisation take place |
- sample dissolved in volatile solvent - then injected through a needle with positive charge at the end - as sample goes through needle it picks up a proton on its way out - the positively charged substance in the sample leave as a fine midst to be accelerated |
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Define volatile |
Something that’s easily evaporated |
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How does electron Spray Ionisation take place |
- sample dissolved in volatile solvent - then injected through a needle with positive charge at the end - as sample goes through needle it picks up a proton on its way out - the positively charged substance in the sample leave as a fine midst to be accelerated |
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Define volatile |
Something that’s easily evaporated |
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General equation for electro spray ionization |
X (g) + H+ > XH+ (g) |
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Advantage of electro spray ionization |
Can’t fragment the sample |
As it’s softer and less “violent” |
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Disadvantage of electro spray Ionisation |
Needle may contain unwanted substances/particles so the sample may by easily contaminated which disrupts the test |
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Define 1st Ionisation energy of an element |
“The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to from 1 mole of gaseous 1+ ions” |
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Define 1st Ionisation energy of an element |
“The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to from 1 mole of gaseous 1+ ions” |
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1st Ionisation of calcium |
Ca (g) > Ca+ (g) + e- |
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Define 1st Ionisation energy of an element |
“The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to from 1 mole of gaseous 1+ ions” |
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1st Ionisation of calcium |
Ca (g) > Ca+ (g) + e- |
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Define 2nd Ionisation energy of an element |
“The energy required to remove 1 mole of electrons from 1 mole of gaseous 1+ ions to form 1 mole of gaseous 2+ ions” |
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Define 1st Ionisation energy of an element |
“The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to from 1 mole of gaseous 1+ ions” |
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1st Ionisation of calcium |
Ca (g) > Ca+ (g) + e- |
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Define 2nd Ionisation energy of an element |
“The energy required to remove 1 mole of electrons from 1 mole of gaseous 1+ ions to form 1 mole of gaseous 2+ ions” |
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2nd Ionisation energy for calcium |
Ca+1 (g) > Ca+2 (g) + e- |
(Only plus one electron at end of equation) |
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Factors that affect Ionisation energies |
1- nuclear charge 2- atomic radius (or number of shells) 3- shielding |
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What’s successive ionisation |
The continuous Ionisation of an element X > X+ > X+2 Etc. |
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What does a big jump in energy required on an energy required/number of electrons graph tell us |
Change of shell |
Successive ionisation |
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What’s the trend in ionization energy down a group and why |
Decreases - shells increase - shielding increase - nuclear charge insignificantly increases - attraction between nucleus and outer electron is less - so less energy required to remove it |
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What’s the trend in ionization energy down a group and why |
Decreases - shells increase - shielding increase - nuclear charge insignificantly increases - attraction between nucleus and outer electron is less - so less energy required to remove it |
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Trend in ionization energy across a period and why |
Increases - shells don’t increase - shielding stays more or less the same - nuclear charge changes significantly - so attraction between nucleus and outer electrons is more - so more energy required to remove electron |
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Why is there a small drop in first ionization energy from group 2 to group 3 |
- group 3 elements’ outer electron is in p sub-shell - group 2 elements’ outer electron in s sub-shell - p sub-shell electrons have higher energy and are further away from the nucleus so they are easier to remove - ADDITIONALLY, electron in p sub-shell will have more shielding - therefore electron in p sub-shell requires less energy to remove than electrons in s sub-shell |
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What’s an example of an anomaly in first Ionisation energy across a period |
The trend is that first ionization energy increases but the elements that don’t follow this trend are - Al (Mg to Al) - S (P to S) - B (Be to B) - O (N to O) |
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Why is there a small drop of first ionization energy between group 5 and group 6 |
- group 5 and 6 outer electrons are in p sub-shell - p sub-shell can hold up to 6 electrons in 3 orbitals - in group 5, there are 3 electrons in the p sub-shell and each orbital contains only 1 electron each - in group 6, there are 4 electrons so one orbital will contain a pair of electrons - this pair of electrons will repel each other - this means it takes less energy to remove one of these electrons than if they were in separate orbitals - therefore the first IE is less in group 6 |
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Why is there a small drop of first ionization energy between group 5 and group 6 |
- group 5 and 6 outer electrons are in p sub-shell - p sub-shell can hold up to 6 electrons in 3 orbitals - in group 5, there are 3 electrons in the p sub-shell and each orbital contains only 1 electron each - in group 6, there are 4 electrons so one orbital will contain a pair of electrons - this pair of electrons will repel each other - this means it takes less energy to remove one of these electrons than if they were in separate orbitals - therefore the first IE is less in group 6 than group 5 |
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What is an orbital |
- a region of space that electrons are most likely to exist in - each orbital can hold a pair of electrons with opposite spins |
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How many electrons maximum can exist in the 1st, 2nd, 3rd and 4th energy level (shell) |
1) 2 electrons 2) 8 electrons 3) 18 electrons 4) 32 electrons |
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How many electrons maximum can exist in the 1st, 2nd, 3rd and 4th energy level (shell) |
1) 2 electrons 2) 8 electrons 3) 18 electrons 4) 32 electrons |
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How many electrons maximum can fit in an s sub-shell, a p sub-shell, a d sub-shell and an f sub-shell? |
S - 2 electrons P - 6 electrons D - 10 electrons F - 14 electrons |
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What are the shapes of s orbitals and p orbitals |
S - spherical P - dumbbell shaped |
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What’s the Aufbau principle |
Lowest energy levels (or shells) fill with electrons first |
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What’s the Aufbau principle |
Lowest energy levels (or shells) fill with electrons first |
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What’s Hund’s principle |
Electrons prefer to occupy orbitals alone and only pair up when there are no orbitals of the same energy left |
The filling up a bus analogy - Antichen |
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What are the three rules for electrons to fill up orbitals |
1) Aufbau principle (lowest energy level ) 2) Hund’s principle (bus analogy) 3) 4s orbital fills before the 3d orbital |
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