1. Give the formula for electron shells
    • 2n2
    • where n is the energy level
  2. The Bohr model is used for what purpose?
    to represent the electron arrangement in an atom for the sake of simplicity
    • If the temperatures are high enough, then 1 or more electrons in an atom can gain enough energy to break away from the atom
    • it is the energy required to remove the outermost electron from an atom/ion
    • 1st ionisation energy: the energy required to remove the outermost electron from one mole of atoms of the element in its gaseous state
    • gradually increase for an atom as the charge being formed increases.
    • markedly increase when an electron is removed from a shell closer to the nucleus
  5. What type of compounds are transition metals generally?
  6. Core Charge of an Atom?
    • the effective positive charge eperienced on the outermost valence electrons in the atom
    • =No. of protons in the nucleus - no. inner shell electrons
    • Dependant on:
    • the number of electrons in the atom
    • the shells they are located in
    • the charge on the nucleus of the atom
  8. What happens to the atomic radius across a period?
    • Decreases
    • This is because the outermost electrons are located in the same shell whilst the core charge increases. This causes a slight increase in the nuclear charge 'felt' on the electrons, which pulls them closer towards the nucleus
  9. What happens to the atomic radius down a group
    Increases because the outermost electron is located within different energy levels meaning that they are further away so that the effective nuclear charge 'felt' is less
  10. Electronegativity
    • the electron-attracting power of an atom in a molecule
    • Metals have low electronegativity because they only have a few, loosely held electrons in their outermost energy level
    • Decreases down a group
    • Increases (left to right) across a period
  11. Metallic bonding
    • low ionisation energies- +ve ions attracted to the mobile, delocalised electrons
    • High electrical conductivity- due to high mobility
    • High thermal conductivity- delocalised electrons vibrate vigorously allowing energy to flow through
    • Malleable and ductile- due to non-directional bonding
    • Various melting/boiling points-due to strong electrostatic bonding. Number of valence electrons vary the amount of energy needed
    • Fairly high density- strong electrostatic bonding & closely packed ions. Varies on no of valence electrons
Card Set
bonding and periodic trends