Electrons, bonding and structure

• Shells are called energy levels.
• Orbitals are the region around the nucleus that can hold up to 2 electrons, with opposite spins due to their similar charges, therefore repel.
• Atomic orbitals are a region of space where there is a high probability of finding an electron.
• S-orbitals are spherical, there is one orbital in every energy level.
• P-orbitals are a dumb bell shape, with 3 orbitals in each energy level from n=2.
• D-orbitals are in each energy level from n=3, and there are 5 orbitals.
• F-orbitals are found in energy levels from n=4, and there are 7 orbitals.
• Electrons have both properties of waves and particles.
• Each orbital will fill with one, before the 1st orbital fills with 2.
• Ionic bonding is the electrostatic attraction between positive and negative ions.
• Giant ionic structure have a high mp, requiring large amounts of energy to overcome the electrostatic attraction.
• Ionic structure can conduct electricity in solution, or molten as their ions become mobile.
• Ionic structures are brittle as sharp blows cause ions to move and contact like ions, therefore repel.
• Ionic structures are soluble and dissolve in polar solvents as water molecules surround ions, and pull them from their structure, breaking the regular lattice.
• Covalent bonding is the electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.
• The attraction of a covalent bond is localised between the shared pair of electrons and the nuclei of the bonded atoms.
• Covalent structures are poor conductors as their molecules are neutral.
• Covalent structure are insoluble due to their non-polar bonds, and have a low mp, as their weak intermolecular forces require little energy to break.
• Boron is in group 3, and bond covalently with 3 other atoms, therefore has a max 6 electrons in it's outer shell.
• Phosphorous, sulphur and chlorine bond with fluorine to give extra molecules, such as SF4 and SF6.
• A dative covalent bond is a bond between two atoms, where both electrons come from on atom which is shown with an arrow.