5.1 - 5.3 Flashcards
How many sub shells are electron shells split into
- 4 sub shells
Name the 4 sub shells
- s
- p
- d
- f
How many orbitals does a s orbital have
- 1
How many orbitals does a p orbital have
- 3
How many orbitals does a d orbital have
- 5
How many orbitals does a f orbital have
- 7
How many electrons can a s orbital hold
- 2
How many electrons can each p orbital hold and so how many electron does a p orbital hold it total
- each orbital can hold 3 electrons
- p orbital holds 6 electrons in total
How many electrons can each d orbital hold and so how many electron does a d orbital hold it total
- each orbital can hold 2 electrons (5 orbitals)
- so in total a d orbital can hold 10 electrons
How many electrons can each f orbital hold and so how many electron does a f orbital hold it total
- each orbital can hold 7 electrons
- so in total a f orbital hold 14 electrons
How many electron can be held in the first shell
2
How many electron can be held in the second shell
8
How many electron can be held in the third shell
18
What is another name for shell number
- principal quantum number
If there is a higher shell number what does this mean
- it means that the shell is further away from the nucleus which mean that it also has higher energy
What is the shape of an s orbital described as
- spherical shape
What is the shape of an p orbital described as
- dumbbell shaped
Name and describe the 3 types of p orbitals
1) Px orbital ( horizontal)
2) Py orbital (vertical)
3) Pz orbital (diagonal)
Define spin-paring
- when 2 electron occupy 1 orbital they ‘spin’ in opposite directions
Define ionic bonding
- compounds that are oppositely charged and held together by strong electrostatic attractions
Describe characteristics of a giant ionic structure
1) regular structure
2) cubic shape
3) giant repeating pattern
What is an example of an ionic compound
- Sodium Chloride
Do most ionic compounds dissolve in water, and if so why?
- yes most of them do dissolve in water, because water molecules are POLAR and they can attract the positive and negative ions and break the structure
Can ionic compounds conduct electricity, if so why?
- yes they can conduct electricity when MOLTEN or dissolved in SOLUTION because the IONS ARE FREE to move around
Do ionic compounds have a high melting point, if so why?
- yes they do have a high melting point as there are many STRONG ELECTROSTATIC forces between oppositely charges ions therefore LOTS OF ENERGY NEEDED TO OVERCOME THESE FORCES
Define covalent bonding
- the sharing of outer electrons in order for the atoms to obtain a full shell with a strong electrostatic attraction
Define a dative covalent bond
- where one atom donates 2 electrons to an atom or ion to form a bond
How are covalent bonds represented
- as lines
How are dative covalent bonds represented
- as arrows
How do you work out the shape of a molecule
- using the number of bond pairs and lone pairs
What do lone pairs do to the shape of a molecule
- they change the shape of bond angles
- they push bonding pairs closer together
- for every lone pair you reduce the remaining bond angles by 2.5 degrees
What would be the name of this shape in a molecule:
Bond pairs= 2
Lone Pairs= 0
Linear (180 degrees)
E.g BeCl2
What would be the name of this shape in a molecule:
Bond pairs= 3
Lone Pairs= 0
Trigonal planar (120)
E.g. BF3
What would be the name of this shape in a molecule:
Bond pairs= 4
Lone Pairs= 0
Tetrahedral (109.5 degrees)
E.g. CH4
What would be the name of this shape in a molecule:
Bond pairs= 5
Lone Pairs= 0
Trigonal Bipyramidal (90 degrees and 120 degrees)
E.g. PCl5
What would be the name of this shape in a molecule:
Bond pairs= 6
Lone Pairs= 0
Octahedral (90 degrees)
E.g. SF6
What would be the name of this shape in a molecule:
Bond pairs= 3
Lone Pairs= 1
Trigonal Pyramidal (107 degrees)
E.g NH3
What would be the name of this shape in a molecule:
Bond pairs= 2
Lone Pairs= 2
Non-linear (104.5)
E.g H2O
What would be the name of this shape in a molecule:
Bond pairs= 3
Lone Pairs= 2
Trigonal planar (120 degrees)
* bond angle remains the same as the 2 lone pairs repel equally from opposite sides
What would be the name of this shape in a molecule:
Bond pairs= 4
Lone Pairs= 2
Square Planar (90 degrees)
E.g XeF4
* bond angle remains the same as the 2 lone pairs repel equally from opposite sides
Define electronegativity
- the ability for an atom to attract electrons towards itself in a covalent bond
What is the most electronegative element
- Fluorine
How do we quantify how electronegative an element is
- Using a Pauling Scale
What does a bigger difference in electronegativity mean
- the more ionic the compound will be
What does a difference of zero in electronegativity mean
- that the compound is purely covalent
How do covalent bonds become polar
- because the atoms attached to it have a difference in electronegativity
Fill in the blanks:
The bigger the difference in electronegativity, the ____ _____ the bond will be
1) MORE
2) POLAR
Are hydrocarbons classed as polar
- No, because the difference in electronegativity is small
True or False:
If the polar bonds are arranged symmetrically then you have no overall polarity
- True
E.g. is CO2
What are the three types of intermolecular bonding in covalent molecules
- London forces
- Permanent dipole- dipole
- Hydrogen bonding
What are London forces
- FORCES THAT EXIST BETWEEN ATOMS AND MOLECULES
How do London forces occur
- as electrons in a molecule or atom can move from one end to another, creating a temporary dipole
- temporary dipole only exists when 2 molecules or atoms are near by
Describe the bonding in Iodine (I2)
- weak London forces holding the I2 molecules together but strong covalent bonds holding the 2 iodine atoms together
What does a bigger molecule or atoms mean for the London force
- the more induced the London forces are as you have larger electron clouds
When we boil a liquid what bond are we breaking
- the intermolecular London forces NOT the covalent bonds as they require more energy to break
What does a longer hydrocarbon mean for the boiling point
- it increases and we need more energy to overcome the intermolecular London forces
What does branched hydrocarbons mean for the boiling point
- it means they can’t pack together as close which weakens the London forces lowering the boiling point
What is permanent dipole-dipole bonding
- interactions that exist in molecules with a permanent polarity
True or false:
Molecules that have permanent dipole-dipole interactions also have London forces too
- true, we just say it has permanent dipole-dipole as that is the strongest forces they have
How do you test polar molecules
- by placing a charged rod near a steady stream of a polar liquid
- you should see the liquid bend towards the rods as the molecules align to face the oppositely charged rod
Define hydrogen bonding
- the strongest intermolecular force that occurs when you have hydrogen interacting with the lone pair on either nitrogen, oxygen or fluorine
How do we show hydrogen bonding
- dotted lines
True or false:
If a molecules has hydrogen bonding it also have permanent dipole-dipole forces and London forces
- True
What is the weakest type of intermolecular forces
- London forces
When you freeze water what happens
- it gets bigger, expands, becomes less dense
Why is ice less dense
- because ice forms a regular structure held by hydrogen bonding. The molecules are further apart which makes ice less dense than water
Why does HF has a high boiling point than HCl
- because HF has hydrogen bonding so more energy is required to overcome the electrostatic forces
Why does HI have a higher boiling point than HCl
- because there is an increase in the mass of the molecule so more London forces so more energy is needed to overcome them
Is the melting and boiling point of simple covalent molecules high or low
- low because you are breaking weak intermolecular forces
