Bonding Flashcards
Metallic bonding definition
Strong electrostatic attraction of positive metal ion surrounded by sea of delocalised electrons
Metallic structure
Giant metallic lattice
Comparing strength of metallic bonds
Mg 2+ and Na +
CRAM
MG has a greater charge of 2+
MG has twice as many electrons in sea of delocalised electrons
MG ions are smaller meaning greater charge identity
Therefore, attraction between MG 2 plus and delocalised electrons are stronger
Four properties of metals
- Conductivity.= good and electrical and thermal conductors as a delocalised electrons help transfer energy through metal very efficiently and delocalised electrons can also flow hence metals also good conduct electricity very well
- Strength of metal= very strong and strong electrostatic attraction between positive metal ions and delocalised electrons
- Malleable and ductile= metals can be hammered into shape which means they are malleable and can be pulled into wires which means they are ductile because of layers of metal ions can slide past one another
- Melting point and boiling point= high melting and boiling points because of strength of metallic bonds
Covalent bond definition
Shared pair of electrons between two atoms
Two types of covalent structures
Macromolecular or simple molecular
Three macromolecular structures
C
Si
SiO2
Strong covalent bonds between atoms
What is diamond and graphite known as?
AlloTropes as there are different structural forms of the same element
Diamond structure
Carbon atoms form 4 covalent bonds
Arrangement is tetrahedral
Very high melting point
Doesn’t conduct a electricity as no free electrons to carry a flow of charge
Graphite structure
Layers of carbon atoms forming three covalent bonds
Delocalised electrons between layers
Separate layers are held by a induced dipole forces
Fairly soft as each layer can slide over each other
Conducts electricity due to delocalised electrons
Still has a high melting point
Simple molecular structures
They have weak intermolecular forces between molecules
Ionic bond definition
Strong electrostatic forces of attraction between oppositely charged ions
Physical properties of ionic compounds
- High melting point on boiling point.
- Electrical conductivity =. Only when aqueous or molten
- Structural properties= Tend to be brittle and shatter easily
Ammonium formula
NH4 +
Hydroxide formula
OH-
Nitrate(v) formula
NO3 -
Nitrate (III) formula
NO2 -
Hydrogen carbonate formula
HCO3 -
Chlorate (I) formula
CLO -
Chlorate ( V) formula
CLO3-
IDE …, instead of ate
No oxygen
Carbonate formula
CO3 2-
Sulphate formula
SO4 2-
Dichromate formula
CR2O7 2-
phosphate formula
PO4 3-
Silver formula
Ag+
Zinc formula
Zn2+
Coordinate bond definition
Shared power electron that both come from the same atom
Three bonding pairs
Trigonal planar
120
Four bonding pairs
Tetrahedral
109.5
Five bonding pairs
Trigonal bipyrimidal
90 and 120
Six bonding pairs
Octahedral
90
One lone pair
Two bonding pairs
V - shape
117.5
1 lone pair
3 bonding pairs
Pyrimidal
107
1 lone pair
4 bonding pairs
See saw
89
119
One lone pair
Five bonding pairs
Square pyramidal
89
Two lone pairs
Two bonding pairs
V - shape
104 ,5
2 lone pairs
3 bonding pairs
Trigonal planar
115
Two lone pairs
4 bonding pairs
Square planar
90
Electronegativity
Ability to attract a pair of electrons in a covalent bond
What atom is most electronegative?
Fluorine
The closer element is the f the more electronegative it is
Three factors that affect electronegativity
Distance from nucleus.
Shielding.
Nuclear charge
What does it mean if a molecule is non polar?
Molecule is symmetrical
Dipoles cancel out
Induced dipole forces of attraction
What does it mean if a molecule polar
Molecule is not symmetrical and dipoles don’t cancel out as atoms have different electronegativities
Permanent dipole forces of attraction
Hydrogen bonding
O-H
N-H
F-H
How does hydrogen bonding arise?
- Large difference in electronegativity between atoms. ( STATE WHCH ATOMS )
- Creates a dipole on the EG O-H BOND ( State the bond )
- Lone pair on oxygen atom in one molecule attracted to to partially positive hydrogen atom on another molecule
How does permanent dipole-dipole arise?
- Difference in electronegativity lead to bond polarity.
- Dips don’t cancel out there for molecule has an overall permanent dipole
- Attraction between partially positive delta plus on one molecule and partial -delta minus on another
How does induced dipole dipole forces arise?
RUTID
1. Random movement of electrons and one molecule lead
2. Uneven distribution of electrons creating a
3. Temporary dipole in one molecule
4. Induce is a dipole in a neighbouring molecule
5. Dipoles a attract
All molecules have induced dipole dipole forces of attraction and therefore can be even stronger than permanent if more atoms which means more electrons
Points to make sure when drawings hydrogen bonding
- Make sure it’s in a straight line.
- Make sure hydrogen bond is labelled
- Make sure hydrogen bond is in a dashed line
4.Make sure you draw all lone pairs on oxygen - Make sure all charge are shown
