3.1.3 - Bonding Flashcards
Definition of ionic bonding
The electrostatic attraction between positive and negative ions. They are non- directional
In ionic bonding what loses electrons and what gains electrons
Metals lose electrons
Non- metals gain electrons
How can your represent an ionic bond ?
What can’t you forget
Using a dot and cross diagram
Don’t forget the charges
Definition of covalent bonding
The electrostatic attraction between a shared pair of electrons and the nuclei of two atoms. They are directional.
How many covalent bonds does group 4 make ?
4
How many covalent bonds does group 3 make ?
3 or more
How many covalent bonds do group 2 make?
2 or more
How many covalent bonds do group 1 make ??
1 or more he p
What is a dative covalent bond ??
Where both electrons come from the same atom
How are dative covalent bond presented ?
The bond is shown by an arrow rather than a straight line
Definition of metallic bonding
The electrostatic attraction between positive ions and delocalised electrons. They are non- directional.
What is the trend across a period of melting point in metals ?
Increase
Charge increases
Electrons increase
Therefore strength of metallic bond is increased
What is the trend of melting point down a group of metals
Decreases Size of ion decreases Charge stays the same Electrons stay the same Mettalic bond strength decreases
Ionic Mp and Bp Conductivity(solid) Conductivity (molten) why? Conductivity (aq) why? Strength why ? Solubility why?
High No Yes -ions free to move Yes-ions free to move Brittle- dislocation lead to layers moving and then repelling each other High - water is polar separates the ions
Metallic
Mp and bp Conductivity(solid) why? Conductivity (liquid) why? Conductivity (aq ) why? Strength Why ? Solubility why ?
High Yes Yes Insoluble Strong can slide over each other Insoluble
Giant covalent
Mp and bp Conductivity (solid) Conductivity (liquid) Conductivity (aq) Strength Solubility
Very highly No No Insoluble Strong for some Insoluble bonds must be broken
Diamond
Structure Bp and mp Conductor Strength Solubility
Giant covalent
Very high bp and mp many strong covalent bonds need breaking
Poor conductor no mobile electrons or ions
Very strong - rigid tetrahedrald arrangement
Insoluble- many covalent bonds must be broken
Graphite
Structure Bp and mp Conductivity Strength Solubility
Very high melting point and boiling point many strong covalent bonds need breaking
Conducts some electrons are free to move
Brittle weak can der waals between layers which can slide over each other
Insoluble- many covalent bonds must be broken
Change of state
What is happening at boiling point
Heat energy is used to break all the bonds a lot. Energy required
Change of state
What happens at melting point
Heat energy breaks some bonds so not as much energy is required
2 bonding pairs
Name
Angle
How it looks
Linear
180
H-Be- He
3 bonding pairs
Name
Angle
What it looks like
Trigonal planar
120
F
//// B - F
<
F
4 bonding pairs
Name
Angle
What it looks like
Tetrahedral -
109.5
H
|
H < C > H
=
=
H
5 bonding pairs
Name
Angle
How it looks
Trigonal bipyramidal
120 and 90
F
F. |
//. P - F
F
6 bonding pairs
Name
Angle
What it looks like
Octahedral
90
F
|
F //S \\ F
F< >F
|
F4 pairs
3 bonding
1 lone pair
Name
Angle
What it looks like
Trigonal pyramidal
107
.. N / | \ H. H. H
4 bonds
2 bonding pairs
2 lone pairs
Name
Angle
Looks like ?
Bent v-shaped
104.5
.. ..
O
/. \
H. H
3 bonds
2 Bonding pairs
1 lone pair
Name
Angle
looks like
Bent v shaped
118
.. S / \ O O
5 bonds
3 bonding pairs
2 lone pairs
Name
Angle
Looks like
T-shape
89
.. F -Cl - F
|
F
5 bonds
4 bonding pairs
1 lone pair
Name
Angle
Looks like
Distorted tetrahedron
89, 103
.. F- S - F < // F F
5 bonds
2 bonding pairs
3 lone pairs
Name
Angle
What it looks like
Linear
180
.. ..
F - Xe - F
..6 bonds
4 bonding pairs
2 lone pairs
Name
Angle
What it looks like
Square planar
90
F F
// .. \\ t
X
F F6 pairs
5 bonding pairs
1 lone pair
Name
Angle
Looks like
Square pyramidal
<90
F
|
F // Br \\F
F F
The order of giving most repulsion in the bonds
Bond pair bond pair
Then
Bond pair lone pair
Then
Lone pair lone pair
Definition of electronegativity
Power of an atom to attract the electrons( electron density) in a covalent bond to itself
What does a higher electronegativity value mean?
More attraction
What is the highest value electronegativity and the lowest?
- 0 - Fluorine
0. 7 - caesium
Electronegativity trend across a period
Increase
Nuclear charge increases
Atomic radius decreases
Therefore more attraction between nucleus and atoms
What is the electronegativity trend down a group
Decrease
Atomic radius decreases
More shielding
Therefore less attraction
What does a delta - show and why ?
Excess of electron density more to that side
What does a delta + show and why ?
Show deficiency of electron density because electrons are further away
List in order of strength the intermolecular forces
Hydrogen bond
Dipole dipole
Van der waals
Explain what van der waals are
Intermolecular force
Occur between all molecules but are only force of attraction in non polar molecules. Weakest
Explain dipole- dipole forces
Intermolecular forces
Occur between polar molecules and add to van der waals
Explain hydrogen bonds
Occur between molecular which contain H bonded to N,O, F have a higher electronegativity. Strongest intermolecular bond
What is the relative bp and solubility of non polar molecules
Low bp only weak van der waals
Insoluble no attraction to polar water molecules
What is the relative bp and solubility of polar molecules
Higher bp strong forces ; dipole-dipole and hydrogen bonds to overcome.
Soluble - attraction to polar water molecules
