1.1 Atomic structure Flashcards

(16 cards)

1
Q

What are the 4 stages of mass spectrometry?

A
  • ionisation, acceleration, separation of ions, detection
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2
Q

Define relative atomic mass:

A
  • the weighted average mass of all the isotopes, relative to 1/12th of the mass of 1 atom of C-12
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3
Q

How are ions accelerated in a mass spectrometer?

A
  • using an electric field
  • they are all accelerated with the same KE
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4
Q

How are ions detected and abundance measured in a mass spectrometer?

A
  • ions gain an electron at the detector which generates a current
  • the size of the current is proportional to the abundance of the ion
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5
Q

Describe the process of electron impact ionisation:

A
  • the sample is injected into the spectrometer and vapourised
  • an electron gun fires high-energy electrons at the sample
  • the high-energy electrons knock an electron off the particles in the sample to form + ions
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6
Q

Describe the process of electrospray ionisation:

A
  • the sample is dissolved in polar volatile solvent
  • injected through a fine hypodermic needle to produce a fine mist
  • needle tip is attached to the positive terminal of a high voltage power supply
  • particles gain a proton (H+ ion) from the solvent to form positive ions
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7
Q

Why do successive ionisation energies increase?

A
  • number of protons stays the same but is attracting fewer and fewer electrons
  • shielding decreases
  • nuclear attraction on the outer electron increases
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8
Q

Give the net equation for the 4th ionisation energy of Mg:

A
  • Mg (g)&raquo_space;> Mg4+ (g) + 4e-
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9
Q

Give the electronic figuration of chromium (Cr):

A

*1s2, 2s2, 2p6, 3s2, 3p6, 3d5, 4s1

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10
Q

Gie the electronic configuration of copper (Cu):

A
  • 1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s1
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11
Q

What is first ionisation energy?

A
  • the energy needed to remove one mole of electrons from one mole of atoms in the gaseous state
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12
Q

Describe the trend in first ionisation energy down a group:

A
  • first IE decreases down the group
  • as you go down the group, atomic radius/shells/shielding increases
  • nuclear attraction on the outer electron decreases
  • less energy needed to remove the outer electron
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13
Q

Describe the trend in first ionisation energy across a period:

A
  • General increase
  • across a period, proton number increases and atomic radius decreases (shells/shielding do not change)
  • nuclear attraction on the outer electron increases
  • more energy needed to remove outer electron
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14
Q

How does first IE change between groups 2 and 3?

A
  • small decrease in first IE
  • outer electron in group 3 element is removed from the p-subshell, which is further away from the nucleus than the s-subshell
  • more shielding makes it easier to remove the outer e- from the group 3 atom than expected
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15
Q

How does first IE change between groups 5 and 6?

A
  • small decreases in first IE
  • in the group 6 atom, the outer e- is removed from a pair in an orbital
  • paired electrons have opposite spins so they repel and are easier to remove than expected
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16
Q

How does first IE change from the end of one period to the start of the next?

A
  • there is a BIG DROP in first IE
  • because the element at the start of the next period has an additional outer shell
  • Increase in shielding and atomic radius
  • so nuclear attraction on the outer e- decreases