Bonding and Structure

A giant metallic lattice

Giant ionic lattice

• Giant molecular - covalent bonding throughout the structure • Simple molecular - weak intermolecular forces.

Strong electrostatic force of attraction between the oppositely charged ions

• Metal transfers its electrons to the non-metal to increase stability of each atom • However, the positive and negative charges do not just point in one direction, they span out to create a giant 3D structure • There is a constant state of repulsion between same charged ions and attraction between oppositely charged ions • All of the forces find a balance as ions form a giant ionic lattice

• Determine charge of metal • Draw metal without its outer electrons • Determine charge of non-metal • Work out formula of ionic compound • Draw the electrons on outer shell as dots on the non metal • Draw crosses on non metal as electrons gained from the metal • Add charges

• High melting points and boiling points, giant ionic lattice structure, many strong electrostatic forces of attraction between ions, requires a lot of energy to overcome - greater ionic charge, stronger ionic bond - smaller atomic radius, stronger ionic bond. • Electrical conductivity - will not conduct electricity in the solid state, ions are in a fixed position. Will conduct electricity in the molten (or aqueous) state, ions are free to move • Dissolve in water, ions make attractions to the different atoms in water and are pulled apart

• A shared pair of electrons between atoms

• When two pairs of electrons are shared between atoms.

Yes BF3 and AlCl3

Yes

If an atom does not use all of its outer electrons, these spare electrons are called lone pairs

• Occurs when one atom provides both the electrons needed to form a covalent bond • Atom donating must have a lone pair, atom receiving must have a vacant orbital • The bond is represented as an arrow pointing to the direction in which the electrons are being given

• Electron pairs repel one another and cause the molecule to adopt a shape which causes for the least amount of repulsion, the electron pairs need to be as far apart as possible • Lone pairs repel more than bonding pairs, they reduce the bonding angle by 2.5 degrees

• Work out a dot and cross diagram and find out how many bonding pairs there are lone pairs and then go from there • If there is a double bond it will repel the same amount as a single bond would

• Linear, 180 degrees, 2 bonding pairs • Trigonal planar, 120 degrees, 3 bonding pairs • Tetrahedral, 109.5 degrees, 4 bonding pairs • Trigonal pyramid, 107 degrees, 3 bonding pairs, one lone pair • Non linear, 104.5 degrees, 2 bonding pairs, 2 lone pairs • Octahedral, 90 degrees, 6 bonding pairs

The ability of an atom to attract a pair of electrons in a covalent bond

• The nuclei are identical and so the attraction to the electrons is equal. the electron density is distributed equally - bond is non-polar

• Nuclear charge of atom (number of protons); higher=greater • Atomic radius of atom; smaller=greater • Number of principle energy levels; fewer=greater

Yes

Fluorine - Small atomic radius and a high nuclear charge

No ability to attract a pair of electrons

• The electron density is distributed unequally resulting in a polar bond • If there is a very large difference, ionic bonding will occur

A covalent bond in which there is an unequal share of the electrons due to the differing electronegativities of the atoms involved