3.1.3 Bonding Flashcards
What do physical/chemical properties of compounds depend on
Depend on the way compounds are held together by chemical bonds and intermolecular forces
Define ionic bonding
The electrostatic attraction between oppositely charged ions in a giant ionic lattice
Describe ionic lattices
Giant, regular repeating arrangement of ions
Crystal structures
Properties of ionic compounds
Strong electrostatic forces require lots of energy to overcome, so they have high melting/boiling points
Once molten, ions are free to move and can conduct an electric current
Often ionic compounds are soluble in water
Define a covalent bond
Electrostatic attraction between the nuclei and the shared pair of electrons
Non metals bonded together
Electron pair(s) shared
Describe singular molecular structures
Although covalent bonds are strong, molecules are not strongly attracted to eachother
Covalently bonded compounds have a small difference in electronegativity
Co-ordinate bonding:
A covalent bond where one of the atoms provides both of the electrons which form the bond
What is coordinate bonding also known as
Dative bonding
Where do arrows point towards in a dative bond
Towards the recipient ion
Describe metallic bonding
Involves the attraction between a ‘sea of delocalised electrons’ and positive ions arranged in a lattice
Properties of metals
Good conductors - delocalised electrons
High melting points - giant structures, electrostatic attraction between positive metal cations and delocalised electrons
Malleable/ductile - ions can slide over each other
What does the strength of a metal depend on
-size of the charge on the ion
-size of the ion
What are crystals
Solids in which the particles have a regular arrangement and are held together by forces of attraction
Four basic crystal types
Ionic
Metallic
Molecular
Macromolecular (giant covalent)
How much stronger are covalent bonds than hydrogen bonds
10 times
What are the two types of bonding in graphite
Strong covalent bonds
Weak van der waals
What is within a hydrogen bond
H bonds with F,O, or N
Another way to say van der walls
Instantaneous dipole
What size molecules have the strongest van der waals
Bigger molecules, since they have a bigger swing of electrons
Elements involved in dipole dipole interactions
C or H and halogen, O or N
Define electronegativity
The tendency of an atom to attract a pair of electrons in a covalent bond
What causes a permanent dipole
When two atoms in a covalent bond have different electronegativies, then electron distribution will be unsymmetrical
What affects the polarity of a covalent bond
The difference in electronegativity
What causes dipoles to cancel out
Linear molecule
Tetrahedral
Why is hydrogen bonding in ice so important
Hydrogen bonding in water causes ice to be less dense
Floats on top of rivers
Insulates ponds
Which area of the periodic table is most electronegative
Top right
What happens to metallic domes after being moulded
Bonds reform to a similar strength
2 bonding pairs
Linear
Bond angle 180
3 bonding pairs
Triangular planar
120 degrees
2 bonding pairs
1 lone pair
Bent
4 bonding pairs
Tetrahedral
109.5
3 bonding pairs
1 lone pair
Trigononal pyramidal
2 bonding pairs
2 lone pairs
Angular, bent
5 bonding pairs
Triangular bipyramidal
90 degrees and 120 degrees
4 bonding pairs
1 lone pair
Seesaw
Notice: lone pair in equatorial plane
3 bonding pairs
1 lone pair
T-shape
Lone pairs in equatorial plane
6 bonding pairs
Octahedral
90 degrees
5 bonding pairs
1 lone pair
Square pyramidal
4 bonding pairs
2 lone pairs
Square planar
