Chapter 3 - Bonding

the result of electrostatic attraction between oppositely charged ions

it can only occur between a metal and a non metal the metal atom loses valence electrons, the non-metal atom gains the valence electrons lost by the metal this interaction forms 2 ions, a positive metal ion and a negative non-metal ion the opposite charges between ions form strong electrostatic forces between the ions the force is the bonding

outer shell electrons

to achieve a noble gas structure

because it makes their arrangements more stable

in a giant lattice

they are brittle they conduct electricity when molten or aqueous only they have high boiling and melting points (usually solid at room temp)

because when the lattice of positive and negative ions distorts, it is easy for same charge ions to come into contact and repel, making the structure break

charged ions can carry charge only if they are free to move, in solids the ions only vibrate on the spot and cannot freely move

ionic compounds exist in a giant lattice, this means that there are very many bonds needed to be broken, so a lot of energy needs to be supplied to the substance

a covalent bond can be defined by the bond formed between two or more non metal atoms (same or different) which is the result of sharing some valence electrons to achieve a noble gas structure

two or more non-metal atoms share some of their valence electrons to form a covalent bond

4 electrons total 2 pairs of electrons

low melting and boiling points poor conductors both solid and molten

intermolecular bonds

electrostatic bonds of attraction form between the positive nucleus and the negative electrons the nuclei of the bonded atoms repel each other as they have the same charge the attractive forces must be stronger than or equal to the repulsive forces for the molecule to form

the electrostatic forces within the molecule are strong, however the intermolecular forces between individual forces are weak and don’t require much energy to overcome

each covalently bonded molecule has a neutral charge because no ions are formed therefore there are no charged particles to carry charge even when the molecules are mobile

this is a type of covalent bond which only occurs when a pair of electrons is provided by one atom but shared between two a co-ordinate bond is indistinguishable from a standard covalent bond once bonded

a pair of electrons on an atom which are both from the same atom and are not being used in a bond

a pair of electrons in which each is from a different atom

an atom which does not have a full outer main level of electrons

the lone pair is indicated and an arrow drawn outwards points to the atomic symbol of the electron deficient atom the charge of the electron deficient atom is indicated

an arrow pointing towards the electron deficient atom if there is a charge, square brackets surrounding the entire molecule and the charge of the electron deficient atom is indicated in the top right corner of the brackets