bonding in all papers (3.1.3)

a bond that contains a shared pair of electrons with both electrons supplied by one atom. once formed is the same as any other covalent bond. this is represented by an arrow.

• ionic • metallic • macromolecular ( giant covalent) • simple molecular

• high mpt and bpt • strong electrostatic forces so a lot of energy is required to overcome.

• less than 20 bonds • covalently bonded molecules held together by weak van der waals forces. • low mpt and bpt

• 2 bonding pairs • 0 lone pairs • 180 bond angle Cl —– Be —– Cl

• 2 bond pairs • 2 lone pairs • 104.5 bond angle O / \ H H

• 3 bond pairs • 0 lone pairs • 120 bond angle F | B / \ F F

• 3 bond pairs • 1 lone pair • 107 bond angle .. N / | \ H H H

• 4 bond pairs • 0 lone pairs • 109.5 bond angle H | C / \ \ H H H

• 5 bond pairs • 0 lone pairs • 90 and 120 bond angles B B \ | B —- A —- B | B

• 6 bond pairs • 0 lone pairs • 90 bond angle F F F \ | / S / | \ F F F

• 4 bond angles • 2 lone pairs • 90 bond angle B B \ .. / A / .. \ B B

• lone pair, lone pair repulsion which is the greatest. • lone pair, bond pair repulsion. • bond pair, bond pair repulsion which is the lowest.

when the negative charge around a covalent bond isnt evenly spread around the orbitals of the bonded atoms.

• the power of an atom to attract negative charge towards itself within a covalent bond. • it increases along a period as atomic radius decreases and decreases down a group as shielding increases.

• exists between polar molecules. • the more electronegative atom draws the negative charge towards itself. • The greater the polarity of a bond or molecule, the stronger the permanent dipole-dipole interactions. • can align to form a lattice of molecules similar to an ionic l lattice.

• can form when the electron orbitals around a molecule are influenced by another charged particle. A + B - A B A + B - A+ B-

• van der waals • permanent dipole • hydrogen bonds

• weakest type • acts as an induced dipole between molecules. • the larger the Mr, the stronger the intermolecular forces. • straight chain molecules experience stronger van der waals forces than branched chain molecules as they can line up and pack closer together, reducing the distance over which the forces acts, therefore stronger.

• strongest type • only forms between hydrogen and the 3 worst most electronegative atoms: . nitrogen . oxygen . fluorine . the lone pair on these atoms forms a bond with a hydrogen atom from another molecule, shown with a dotted line. • much hight mpt and bpt

• Cl has a higher electronegativity than the C • Electron density is unsymmetrical

• random movement of electrons forms a temporary dipole • induces a dipole in another molecule • dipoles in different molecules attract

• silcon oxide is a giant covalent molecule • it has very strong covalent bonds • phosphorus oxide is a simple covalent molecule • it has weaker van der waal forces between molecules

• polarity is evenly distributed • dipoles cancel out