Bonding Flashcards
what is ionic bonding
the result of electrostatic attraction between oppositely charged ions
how are electrons transferred in ionic bonding
electrons transferred from the metal to the non metal
what do ionic compounds exist as
lattices that are strong because of the electrostatic attraction that acts in all directions and extends throughout the lattice
Electrical conductivity in ionic bonding
can’t conduct when solid since ions are not free to move and carry charge
can when molten or in solution
Melting points in ionic bonding
High because the electrostatic forces of attraction which act in all directions require a lot of energy to overcome
solubility in ionic bonding
tend to be soluble in polar solutions since the ions are pulled by the solvent causing them to dissociate away from the lattice and dissolve
Why are ionic compounds brittle
They contain a lattice of alternating positive and negative ions in fixed positions so when force acts on it from one side it shatters
Covalent bonding
Sharing a pair of electrons between two non metals to have a more stable electron configuration
How are covalent bonds held together
The forces of repulsion and attraction are equal so it keeps the particles at the same distance
Why can’t simples covalent structures conduct
Because there are no delocalised electrons or ions that are free to carry charge can’t conduct in solution either
Are covalent mp and no high or low
Low
Why are covalent mp and bp low
Weak intermolecular forces between molecules which require little energy to overcome
How can acids conduct electricity in water
Acids are covalent but they become ions in water
What is it called when both electrons are shared from one atom covalently
Coordinate bonding
What is coordinate bonding
Where both shared electrons are from one atom
How is coordinate bonding shown
As an arrow
How does coordinate bonding happen
The atom accepts it doesn’t have a full outer shell (electron deficient)
The donating atom donates a non bonding pair of electrons ( a lone pair)
What is metallic bonding
Bonding WITHIN a metal
What are metallic bp and mp like
Very high since there are strong electrostatic forces of attraction which acts in all direction throughout the lattice which requires alot energy to overcome
Why are metals good conductors
They have a sea of delocalised electrons free to carry charge and thermal energy
What does ductile mean
Can stretch it into a wire
What does maleable mean
Can be bent
Are metals maleable and ductile
Because layers can slide over each other and electrons move with them
How can you increase the strength of a metal
Make it an alloy so layers can’t slide
What is an alloy
When you add another element to a metal
How do we know particles in a solid are arranged regularly
It has a fixed shape
How do we know solids vibrate around a certain point
When it is heated it expands and there is no diffusion
What does jostling mean
Move around each other
How do we know that liquids have a random particle arrangement
Particles can move around each other and fill a container
How do we know that particles in a liquid are close together
It can’t be compressed
How do we know that particles in a liquid jostling
Slow diffusion and convection of heat
How do we Know that particles are arranged randomly in a gas
Fill a containerc
How do we know that particles in a gas are far away from each other
Easily compressed
How do we know particles in a gas move rapidly
Can exert pressure on a surface
Convection
Quick diffusion
Enthalpy change of melting
Solid to liquid energy supplied to weaken forces acting between particles
Temp doesn’t change when heat energy is supplied because it’s absorbed as the forces are weakened
Electronegativity
The power of an atom to attract the shared pair of electrons in a covalent bond towards it self
On a scale of 0-4 ( highest is 4)
What three elements have the highest electronegativity
FON
Fluorine. Oxygen. Nitrogen
What affects electronegativity
Affective nuclear charge. Distance from the nucleus. Shielding
How does electronegativity charge across a period
Increases
How does electronegativity change down a group
Decreases down a group
Why does electronegativity increase across a period
Because of a higher affective nuclear charge despite more shielding
Why does electronegativity decrease down a group
Due to increased shielding although there’s a higher affective nuclear charge
Why does electronegativity decrease down a group
Due to increased shielding although there’s a higher affective nuclear charge
What type of bonding does polarity refer too
Covalent
What is polarity
The unequal sharing of electrons between atoms in a bond
How are there non polar covalent bonds
If the atoms are the same. Eg chlorine and chlorine
What happens in polar bonding
Electron cloud is distorted ( pulled) towards the more electronegative element
What does intra mean
Within
What does inter mean
Between
What type of bond contains intermolecular forces
Covalent only
What are the three types of intermolecular forces
Van der walls
Dipole-dipole
Hydrogen bonds
What is the weakest type of intermolecular force
Van der waals
What is the strongest type of intermolecular force
Hydrogen bonding
Intermolecular forces strength in order weakest to strongest
Van der waals
Dipole dipole
Hydrogen bonding
What molecules or atoms does van der waals happen in
All atoms and molecules (Nobel gasses)
Where does dipole dipole happen
Between certain types of molecules
Where does hydrogen bonding happen
Between certain types of molecules
Dipole moment
Sums up the effect of polarity of all the bonds in a molecule
Are non polar or polar things dipole and why
Polar things are dipole because there is permanent dipoles
Non polar don’t have dipole forces
What type of faint force are dipoles
Electrostatic forces of attraction
Non polar things are often shaped and have
Symmetrical and have the same groups
Dipole dipole definition
Forces that act between two molecules that have permanent dipoles
They orientate themselves to attract each other
Van der waals summary
Positive and negative charges in everything that are overall neutral
Always very weak electrostatic forces of attraction in everything
Electrons constantly move and so do their distribution of charge
How does van der waals happen
Two neutral neighbouring atoms
One has a dipole due to charge distribution
Induces a dipole in the neighbouring atom
What elements are hydrogen bonds between
The FON and hydrogen
Fluorine oxygen or nitrogen
Why do only the fon make hydrogen bonds
Only ones that are electronegative enough
How are hydrogen bonds shown
- dashes
What happens down the group of the Nobel gasses and why
BP increases due to the increased number of van der waals because there are more electrons
What type of crystal is graphane
Giant covalent
What does a higher bond enthalpy mean
More energy is needed to break the bond
It is a stronger bond
Displayed formula
Shows all the atoms and the bonds with a line and their element
Structural
Order of atoms without showing bonds
Skeletal
Lines that show single carbon to carbon bonds
Homologous series
Series of organic compounds with the same functional group but different carbon chain length
Physical properties of a homologous series
Different melting and boiling points
Different viscosity
Ones that contain O or N would decrease in solubility since it becomes non polar
Chemical properties of a homologous series
Similar chemical reactions
Meth
1
Eth
2
Prop
3
Pent
5
Hex
6
Hept
7
Oct
8
Non
9
Dec
10
Cyclo
It’s joined up in a ring
(Like pentose in DNA)
But
4
How are bond broken
When something has a higher energy than it
