Topic 1 Atomic Structure

• What is the relative mass of a proton? [1]


  1
• What is the relative mass of a neutron? [1]


  1
• What is the relative mass of an electron? [1]

  1/2000
• What is the relative charge of a proton? [1]

  +1
• What is the relative charge of a neutron? [1]

  0
• What is the relative charge of an electron? [1]

  -1
• What is an isotope? [1]

  Isotopes of an element are atoms with the same number of protons but different number of neutrons
• Define relative atomic mass (Ar) [2]

  The average mass of an atom of an element on a scale where an atom of carbon-12 is 12.
• Define relative isotopic mass [2]

  The mass of an atom of an isotope of an element on a scale where an atom of carbon-12 is 12
• Define relative molecular mass (Mr) [2]

  The average mass of a molecule on a scale where an atom of carbon-12 is 12
• Name the 4 step process of the Time Of Flight mass spectrometer [4]

  Ionisation

  Acceleration

  Ion drift

  Detection
• What is the process of electrospray ionisation? [2]

  The sample is dissolved and pushed through a small nozzle at a high pressure. A high voltage is applied to it, causing each particle to gain a H+ ion. The sample is turned into a gas made up of positive ions.
• What is the process of electron impact for ionisation of the ToF mass spectrometer? [2]

  The sample is vapourised and an electron gun is used to fire high energy electrons, this knocks off one electron off each particle so they become +1 ions.
• What is the process of acceleration for the ToF mass spectometer [2]

  The positively charged ion are accelerated by an electric field so that the all have the same kinetic energy. The lighter ther ion is the faster it reaches the detector.
• What is the process of ion drift in the ToF mass spectrometer? [2]

  The ions enter a region with no electric field so they just drift through it. Lighter ions will drift through faster than heavier ions.
• What is the process of detection for the ToF mass spectrometer? [2]

  Because lighter ions travel at a higher speed in the drift region, they reach the detector in much less time than the heavier ions. The detector detects charged particles and a mass spectro.
• Define the first ionisation energy of an atom [2]

  The first ionisation energy is the energy needed to remove 1 electron form each tom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions.
• What does having a high ionisation energy mean? [2]

  A Hugh ionisation energy means that there’s a high attraction between the electron and the nucleus and so more energy is needed to remove the electron.
• Define the meaning of second ionisation energy of an atom [2]

  The second ionisation energy is the energy needed to remove 1 electron from each ion in 1 mole of gaseous +1 ions to form 1 mole of gaseous 2+ ions.
• What are the three factors effecting ionisation energies? [3]

  Nuclear charge

  Distance from nucleus

  Shielding
• How does nuclear charge affect ionisation energies? [2]

  The more protons there are in the nucleus, the more positively charged the nucleus is and the stronger the attraction for the electrons.
• How does distance from nucleus affect ionisation energies? [2]

  Attraction falls off very rapidly with distance. An electron close to the nucleus will be much more strongly attracted than one further away.
• How does shielding affect ionisation energies? [2]

  As the number of electrons between the outer electron and the nucleus increases, the outer electrons feel less attraction towards the nuclear charge. The lessening of the pull of the nucleus by inner shells of electrons is called shielding.
• Explain how the ionisation energies of group 2 decrease going down the group [4]

  If each element down group 2 has an extra electron shell compared electrons to the one above, the extra inner shells will shield the outer electrons from the attraction of the nucleus.

  Also, the extra shell means that the outer electrons are further away from the nucleus , so the nucleus attraction will be greatly reduces thus reducing the energy needed to remove the electron.
• Explain how across period 3 the ionisation energies increase [4]

  The ionisation energies increase because the number of protons is increasing, which means a stronger nucleus attraction. All the extra electons are at roughly the same energy level, even if the outer electrons are in different orbital types, this means there’s generally little extra shielding effect on the extra distance to lessen the attraction from the nucleus.
• Why is there a drop in ionisation energies between group 2 and group 3? [1]

  Subshell structure
• Why is there a drop in ionisation energies between group 5 and group 6? [1]

  Electron repulsion
• How do the electron shells fill up? [1]

  1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
• Name the electron configuration of chromium [1]

  1s2 2s2 s2p6 3s2 3p6 4s1 3d5
• Name the electron configuration of copper [1]

  1s2 2s2 2p6 3s2 3p6 4s1 3d10
• Name the electron configuration of bromine [1]

  1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
• Name the electron configuration of Vanadium [1]

  1s2 2s2 2p6 3s2 3p6 4s2 3d3