Structure and bonding

• A pure covalent bond consists of a shared pair of electrons
• pure covalent bond is when both atoms have the same electronegativity ( amount of electrons)
• Diatomic atoms are pure covalent bonds
• In polar covalent bonds one element is more electronegative ( which makes them stronger ) and pulls the other element towards it
• Dipole where one atom ( the more electronegative one ) has a partial positive charge and the other has a partial negative charge
• Ionic bonds are formed between a metal and a non-metal
• Pure covalent bonds have no difference in electronegativity
• Polar covalent have a low difference in electronegativity between the atoms
• Ionic bonds have a high difference in electronegativity between the atoms
• Intermolecular bonds are between molecules
• London dispersion forces are the weakest type of intermolecular forces
• London dispersion forces are caused by an uneven distribution of electrons in the outer shell of atoms resulting in a slightly negative and a slightly positive charge on either side of the atom called a temporary dipole
• A temporary dipole on one atom can induce a temporary dipole in another neighbouring atom.
• London dispersion forces are the electrostatic attractions between the slightly positive end of one atom and the slightly negative side of the other atom.
• Molecules with a permanent dipole are polar
• Hydrogen bonding is the strongest type of intermolecular bonds
• If a molecule is not polar it is symmetrical like carbon tetrachloride
• If a molecule is not symmetrical like water it is polar
• All ionic compounds have a high melting and boiling point
• when ionic compounds are dissolved in water or are molten , the ions are free to move around which makes them able to conduct electricity and heat
• All covalent network structures have a very high melting and boiling point
• Water is denser than ice
• Water has a high surface tension
• Metallic bonding is the electrostatic force of attraction between the metal atoms and the delocalised electrons
• The strongest to weakest bonds are covalent bonds hydrogen bonds permanent dipole interactions and London dispersion forces.