Chemical bonding Flashcards
1
Q
What is an ion?
A
A charged atom or group of atoms
2
Q
What is an ionic bond?
A
It is the force of attraction between opposite charge ions in a compound. They are always formed by the transfer of electrons from one atom to another.
3
Q
What is octet rule?
A
When burning occurs, atoms tend to reach an electron arrangement with a electrons in the outermost energy level
4
Q
Define a compound
A
It is a substance that is made up of two or more different elements combined chemically together
5
Q
When you’re writing the ionic formula of compounds, what should you remember about the charge overall?
A
It should have a neutral charge overall in the compound
6
Q
What are metals have the tendency to do in terms of the loss and gain of electrons?
A
Metals tend to lose electrons
7
Q
Do nonmetals tend to gain or lose electrons?
A
Nonmetals tend to gain electrons
8
Q
What is the charge of a hydroxide ion?
A
OH minus
9
Q
What is the charge of a nitrate ion?
A
N03 minus
10
Q
What is the charge of a hydrogen carbonate ion?
A
HCO3 minus
11
Q
What is the charge of a permanganate ion?
A
MNO4 minus
12
Q
What is the charge of a carbonate ion?
A
CO3 2-
13
Q
What is the charge of a chromate ion?
A
CRO4 2-
14
Q
What is the charge of a dichromate iron?
A
Cr2O7 2-
15
Q
What is the charge of a sulfate ion
A
SO4 2 minus
16
Q
What is the charge of a sulphite? Ion
A
SO3 2 minus
17
Q
What is the charge of a thiosulphate ion?
A
S203 2-
18
Q
What is the charge of a phosphate ion?
A
PO4 3-
19
Q
What is the charge of an ammonium ion?
A
NH4 +
20
Q
Why is it not possible to predict the charges of transition metals
A
They have a variable valence
21
Q
Give me some characteristics of transitional metals
A
They have a variable valances apart from scandium and zinc
They form coloured compounds
They are widely used as catalysts however a scandium and zinc show little catalytic activity
22
Q
Define a transitional metal
A
It is one that forms at least one I am with a partially filled the sublevel
With the exception of zinc and scandium
23
Q
Define a molecule
A
It is a group of atoms joined together. It is the smallest particle of an element or compound that can exist independently
24
Q
Why do transition metals exhibit variable valance
A
The S and d orbitals or transitional metals are very close in energy. So electrons from both orbitals can be lost or shared.
Disability of different oxidation states depends on factors like the nature of the compound and the surrounding environment
25
Why are the noble gases so stable?
Their outermost electron shells are fully occupied, making them highly unreactive so they are already adeer to the OCTET room
26
What are the uses of helium?
Breathing mixtures used in sea diving to prevent nitrogen narcosis
It is used as a coolant and Cryo genetics as it has a low boiling point so it is suitable for cooling system
It is used in balloons and airships as it is lighter than air and non-flammable
27
What is argon used for?
Welding as it is unreactive so protect molten metals from reacting with oxygen and nitrogen in air
Lightbulbs
Preservation of historical documents and materials by creating an inert atmosphere around these things so it prevents them from reactive with oxygen and moisture in the air
28
What is covalent bonding?
It is the sharing of electrons to complete outer shells
29
What are the exceptions of the OCtet rule
Hydrogen follows the due as it needs only two electrons
30
What are some characteristics of ionic compound?
They conduct electricity when molten or dissolved in the solution
They have a high melting boiling point due to the attraction between ions
Existing solids at room temperature
31
What are some everyday uses of ionic materials?
Salt tablets – used to replace salt lost during sweating
Water softening – they can be used to remove calcium and magnesium ions from hard
32
What is a pure covalent bond?
It is where two atoms share electrons equal equally
33
Give an example of a polar covalent bond
H2 and CL2
34
What are double covalent bond?
It is a bond where two atoms share two pairs of electrons resulting in a stronger and shorter bond compared to a single bond
35
Give an example of a double covalent bond
02
36
What is the triple covalent bond?
It is a bond to Adam share three pairs of electrons making it the shortest and strongest type of covalent bond
37
Given an example of why you would find a triple covalent bond
N2
38
What is a pie bond?
It is formed by the sideways overlap of P orbitals
39
What is a sigma bond?
It is the head on overlap of two orbitals
40
What bond occurs first?
Sigma and then every bond after is a bond
41
What is the strongest type of bond sigma or pi?
Sigma bonds are stronger as there is more overlapping of orbitals
42
What are the characteristics of covalent substances?
They have a low melting and boiling point because the intermolecular forces are relatively weak between molecules
They are generally insoluble in water but soluble in non-polar solvents
They are soft and brittle
They cannot conduct their electricity
43
Is the difference between a sigma and a pie bond?
Sigma bonds involve the head on overlap of orbitals whereas the pi bonds involve sideways overlaps
44
Can you find pie bonds in all types of bonds?
No pie buns are only found in multiple bonds they are not found in single bonds
45
What are polar covalent bonding?
It is when atom share electrons unequally due to differences in electronegativity causing a partial positive charge and one item and the partial negative one another
46
Give an example of a polar covalent bond
Water
This is due to oxygen being more electronegative than hydrogen causing unequal of electrons
47
What is non-polar covalent bonding?
It is when two atoms share electrons equally because they have identical or very similar electronegativity
48
What is an example of a non-polar covalent bond?
Oxygen gas molecule O2
Both atoms have the same electronegativity so they pull the shared electrons equally to each other leading to no partial charges on either atom
49
How can you test for the polarity for liquids?
You can use a charged plastic rod and observe how liquids react
Polar liquids are attracted to the rod because they have diapers
Nonpolar liquids will not be attracted to the charge rod and they have no dipoles
50
Are ionic substances soluble in water?
Yes, as the solvent molecules can separate and surround the ions
51
Are polar covalent compounds soluble in water?
Yes, as water is also polar so it can pull the polar molecules in the covalent bond apart from each other
52
Are nonpolar covalent compound soluble and water?
No, as they cannot form strong interactions with polar water molecules so cannot be broken apart easily
53
Define electronegativity
It is a measure of an atom ability to attract the shared pair of electrons in a covalent bond
54
What does the electronegativity difference need to be if the bond is polar covalent
It needs to be between 0.4 and 1.7
55
If an electronegativity difference is greater than 1.7 what is the bond said to be?
Ionic as the electrons are fully transferred from one atom to another
56
If the electronegativity value is between zero and 1.4, what does this mean about the bond?
It is a nonpolar covalent bond
57
What element has the highest electronegativity?
Fluorine
58
Why are Scandi and zinc different to other transition metals?
They only form a white compound
They only form one I on each
They show little ability to act as a catalyst
59
What are bond pairs?
They are pairs of electrons involved in bonding
60
What are loan pairs?
They are pairs of electrons not involved in bonding
61
What repels more loan pairs or bond pairs?
Loan pairs
62
If you have two bond pairs, what kind of VESPR molecule shape do you get?
Linear with a bond dangle of 180°
63
If you have three bond pairs, what kind of VESPR molecule do you get?
Trigonal planner with a bond angle of 120°
64
If you have four bond pairs, what VSBN molecule do you get?
Tetrahedral
And you have a angle of 109.5°
65
If you have a molecule that has three bond pairs and one loan pair, what kind of Vespr molecule do you get?
Pyramidal with a bond angle of 107°
This is because the loan pays push the bond pairs together more than if the loan power wasn’t there like in a tetrahedral
66
What is intermolecular forces?
They are the forces between molecules
67
What are intra molecular forces?
They are forces within a molecule that hold the atom together
68
What are the types of intermolecular forces?
Vander Wells forces
Permanent dipole forces and hydrogen bonding
69
What are Vander Wells’s forces?
They occur between non-polar molecules
In a nonpolar molecule electrons are constantly moving around. This means that anyone moment the electrons may both be on one side of the molecule giving it a slight charge. This is a temporary dip.
The formation of temporary dimples can induce a similar dipole in a nearby molecule resulting in an attraction between the two molecules
70
If an electronegativity difference is less than or equal to 1.7 what is it indicate about the bonding in a compound?
It is covalent
71
Define Vanderwell’s forces
They are a weak attractive forces between molecules forming from the formation of temporary temples. They are the only forces of attraction between nonpolar molecules.
72
73
As molecules get bigger, what happens to Vanderbilt forces?
The bigger the molecule of the more electrons meaning that there is a higher chance of temporary dip forming so down Vanderwell’s forces get stronger
74
What are dipole dipole forces?
These occur between polar covalent molecules, e.g. molecules with a permanent dipole
When two molecules with a permanent dipole are close together, the sides of the molecules with opposite charges are attracted to each other . E.g. If two molecules of HCL come close to each other the positive side of the hydrogen will be attracted to the negative side of the chlorine in another molecule
75
Are dipole dip forces stronger than Vanderwell?
Yes, as polar molecules have a much higher boiling point and melting point that non-polar molecules some more energy is needed to break the bonds
76
Define dip dip forces
They are the forces of attraction between the negative pole of one polar molecule and the positive pole of another polar molecule
77
Define hydrogen bonding
They are a type of dip dipole attraction between molecules in which hydrogen atoms are bonded to nitrogen and oxygen or flooring. The hydrogen atom carry a partial positive charge and is attracted to the electronegative atom in another molecule.
78
Explain hydrogen bonding
Hydrogen is bonded to either nitrogen oxygen or flowing. The partial charges are particularly strong as there is a big electronegativity difference between the molecules.
It means that hydrogen bonding is the strongest form of intermolecular forces
Hydrogen carries a positive charge whereas fluorine oxygen and nitrogen carry negative charge so they are attracted to each other
79
What kind of line in the drawing of hydrogen bonding represents hydrogen bonding
A dotted line
80
Order the different types of intermolecular bonding from weakest to strongest
Vanderwell of the weakest
Dip dip
Hydrogen bonding is the strongest
81
What can you dissolve nonpolar solute in?
Cyclohexane
82
What do you need to remember when talking about dissolving compounds and water?
Like dissolves like
