Atomic Stucture

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A2 Chemistry (Physical 1) Mind Map on Atomic Stucture, created by Dominic Weston on 23/01/2018.
Dominic Weston
Mind Map by Dominic Weston, updated more than 1 year ago
Dominic Weston
Created by Dominic Weston about 6 years ago
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Resource summary

Atomic Stucture
  1. Ions
    1. Ions have different numbers of protons and electrons
      1. Ions formed by gaining or losing electrons from the atom
        1. Positive ions have lost electrons
          1. Negative ions have gained electrons
            1. Negative Ions repel
    2. Isotopes
      1. Same element with different numbers of neutrons
        1. Number and arrangement of electorns decide the chemical properties of an element
          1. Isotopes have the same electrons / config so same chemical porperties
            1. Slightly different physical properties due to different mass of atom
        2. ToF Mass Spectrometer
          1. Ionisation
            1. Electron Impact
              1. Sample is vaporised
                1. High energy electrons fired at sample from an electron gun
                  1. Forms +1 ions that are attracted to -ve plate
              2. Electrospray
                1. Sample dissolved in volatile solvent
                  1. Injected through fine needle
                    1. Tip of needle attached to +ve end of high-voltage supply
                      1. Forms +1 ions by gaining a proton from solvent
              3. Detection
                1. Positive ions discharged
                  1. By gaining electrons when hit detector
                    1. Generates a current from the movement of electrons
                      1. Size of current indicates number of ions hitting plate
                        1. Mass spectrum
                          1. Data used to produce graph
                            1. mass to charge ratio (m/z) against abundance
                              1. used to work out relative atomic mass of element
                                1. = mass of isotopes / abundance
                            2. Greatest m/z value
                              1. Tells us the relative mass of sample
                                1. small signal may be above it
                                  1. this is due to ions having higher mass on a single atom
                                    1. Signals below are due to fragmentation of molecular ions
                      2. Flight Tube
                        1. Low mass, faster
                          1. Fastest meets detector first
                        2. Acceleration
                          1. +1 ions accelerated using electric field
                            1. So that they all have the same kinetic energy
                              1. Velocity depends on mass
                                1. low mass, faster
                          2. Instrumental method of analysis
                            1. Used to find abundance and mass of each isotope of an element
                              1. This allows us to find its relative atomic mass
                                1. Used to find relative molecular mass of substances of molecules
                            2. Electronic Structure
                              1. Electron shells made up of sub-shells and orbitals
                                1. Electrons move around nucleus in regions of an atom - shells or energy levels
                                  1. Shells are divided into sub-shells which have slightly different energies
                                    1. Sub-shells have different numbers of orbitals which can each hold 2 electrons
                                      1. Two electrons in each orbital spin in opposite directions due to repulsion
                                        1. 1s^2 - 1 orbital, 2e-
                                          1. 2p^6 - 3 orbitals, 6e-
                                            1. 3d^10 - 5 orbitals, 10e-
                                              1. 4f^14 - 7 orbitals, 14e-
                                        2. Further the shell is from the nucleus, the higher its energy
                                          1. Number of outer shell electrons decide chemical properties
                                            1. Group 1 and 2 easily lose electrons from outershell to from positive ion
                                              1. Group 5, 6 ,7 can gain 1, 2, 3 electrons form negative ions
                                                1. Group 4, 7 share electrons to form covalent bonds
                                                  1. Group 0 have filled sub-shells, dont react making them inert
                                                    1. Transition metals lose s, d electrons forming positive ions
                                                      1. Transition metals are unusual
                                                        1. Copper and Chromium fill their 4s sub shell singly
                                                          1. Energetically more favourable to fill 3d sub shell first
                                                            1. They also lose the 4s electron before 3d when becoming ions
                                                2. Form inert gas configuration
                                            2. Ionisation Energy
                                              1. Ionisation - removal of electrons from atoms or molecule
                                                1. Factors
                                                  1. Nuclear Charge
                                                    1. more protons in nucleus, stronger the attaction to electrons
                                                    2. Shielding
                                                      1. More electrons between nucleus and outer electron, less attaction between the two
                                                      2. Nucleus Radii
                                                        1. Attraction falls off rapidly with distance, larger the radii, less attaction
                                                      3. Trends
                                                        1. Across any period
                                                          1. Increase harder to remove outer electron
                                                            1. Across period increasing nuclear charge, more protons
                                                              1. Shielding the same across
                                                                1. More attaction between the electrons and protons
                                                          2. Down a group
                                                            1. Extra electron shells
                                                              1. Less attraction between positive nucleus and outer electron
                                                                1. Furthest electron far away
                                                            2. ALM
                                                              1. Despite increase in nuclear charge,
                                                                1. Outer Al electron in a higher energy sub-shell
                                                                  1. increase shielding
                                                                    1. Less energy needed to remove the electron
                                                                  2. Same shielding, same orbital
                                                                    1. Phosphorus has 1 fully occupied orbital
                                                                      1. Repulsion in the electron orbital
                                                                2. SLP
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