C3) Bonding

• Ionic bonding occurs between metals and non-metals
• Metallic bonding occurs between metals.
• Covalent bonding occurs between non-metals and non-metals.
• In ionic bonding, electrons are transferred from metals to non-metals
• Ionic bonding is the result of electrostatic attraction between oppositely charged ions.
• Ionic compounds are always solid at room temperature
• Ionic compounds have giant structures and therefore have high melting and boiling points
• Ionic compounds are conductive when molten or aqueous when electrons are free to move and carry the charge.
• Ionics compounds are brittle and shatter easily.
• Covalent bonding is the sharing of electrons
• In a double covalent, 4 electrons are shared.
• Covalently bonded structures cant conduct electricity as it is overall neutral.
• Dative or co-ordinate covalent bonds are when an electron pair is donated fro one atom to another.
• Co-ordinate bonds are the same strength as covalent bonds
• Metals can't transfer electrons
• Metallic bonding, consists of a lattice of positive ions containing a 'sea' of delocalised electrons
• Metals are often in layers meaning that they are usually malleable and ductile.
• Delocalised electrons carry charges around the lattice and can move freely in the lattice
• The greater the charge of a metal, the greater the number of delocalised electrons present.
• Metals generally have higher melting and boiling points as they have giant structures
• Electronegativity is the power of an atom to attract the electron density in a covalent bond towards itself.
• Electronegativity depends on:

  The nuclear charge

  The distance between the nucleus and the outer shell

  The shielding of the nuclear charge by electrons in inner shells
• Electronegativity increases across a group (The atomic radius decreases, shielding increases, more nucleons and more electrons.)
• Hydrogen bonding > Di-pole di-pole bonding > Van Der Waals
• Daddy NOF (hydrogen bonding)
• Van Der Waals forces are temporary dipoles created by the random movement of electrons, inducing a temporary dipole in the neighbouring molecule (TIDDI force)
• Permanent dipole-dipole attraction is the attraction between polar molecules.
• Lone pair- lone pair repulsion is strongest while bonded pair- bonded pair repulsion is the weakest