T4: Bonding Flashcards
metallic structure
giant lattice (regular arrangement of particles)
metallic bonding
strong metallic bonds
metallic structure and bonding definition
strong electrostatic attraction between positive metal ions surrounded by a sea of delocalised electrons
comparing the strength of metallic bonds (the bonding in Mg is stronger than in Na)
- Mg2+ has a greater charge of 2+
- Mg2+ ions are smaller
- attraction between the Mg2+ ions and the delocalised e- is stronger
properties of metals conductivity
they have delocalised e-
properties of metals strength of the metal
strong electrostatic attraction between the positive metal ions and delocalised e-
properties of metals malleable and ductile
layers of metal ions can slide past one another
properties of metals melting and boiling points
strength of the metallic bonds
covalent structure
macromolecular or simple molecular
covalent bonding
strong covalent bonds
covalent structure and bonding definition
a shared pair of electrons between 2 atoms
How does sharing e- hold atoms together
The attraction forces are stronger than the repulsion forces and therefore the atoms are held together
3 macromolecular structures
- carbon
- silicon
- silicon dioxide
2 macromolecular crystals
- diamond
- graphite
diamond characteristics
- each C has 4 covalent bonds
- tetrahedral shape
- very high mp
- very hard
- non-conductor
graphite characteristics
- layers with 3 covalent bonds to each C
- high mp
- each C has delocalised e-
- layers held together by weak intermolecular forces
- soft layers can slide over each other
- conductor (has delocalised e-)
examples of simple molecular structures
H2O (water)
NH3 (ammonia)
Cl2 (chlorine)
O2 (oxygen)
CH4 (methane)
example of drawing simple molecular structure (I2)
3 molecules each with 2 atoms covalently bonded with intermolecular forces between the molecules
forces and properties of simple molecular structures
- intermolecular forces act between molecules
- simple molecular substance boils intermolecular forces break
- intermolecular forces weaker than covalent bonds so simple molecular compounds have low mp
ionic structure
giant lattice
ionic bonding
strong ionic bonds
ionic structure and bonding definition
an ionic bond is the strong electrostatic attraction between oppositely charged ions
drawing the structure of an ionic compound
physical properties of ionic compounds high mp + bp
strong electrostatic attraction
physical properties of ionic compounds electrical conductivity
solid -> ions fixed in lattice so cannot move
aqueous / molten -> ions can now move and conduct electricity
structural properties tend to be brittle + shatter easily
when an external force is applied the layers of ions shift and like charges repel causing the crystal to crack
molecule definition
a group of atoms which are covalently bonded to 1 another
coordinate bond definition
a shared electron pair which have both come from the same atom
covalent bond =
bonded pair
coordinate bond =
lone pair
model ans lone pair donation question
lone pair of electrons on the X+ / X- is donated to Y
valence definition
the outer shell of electrons (e- used in bonding)
to minimise their (bonding and lone pairs) repulsion…
the e- pairs repel each other as far apart as possible
strength of repulsion between lone and bonding pairs equation
lone pair to lone pair > lone pair to bond pair > bond pair to bond pair