6. IONIC BONDING Flashcards
1
Q
- What is a Qualitative form of a chemistry law?
A
- it is a law that is written out in words
2
Q
- What is a Quantitative form of a chemistry law?
A
- it is a law that is written in the form of a chemical formula
3
Q
- What is the scientific definition for Coloumb’s Law?
A
- Two point charges in free space or air exert a force on each other.
- The force is directly proportional to the product of the charges
- and inversely proportional to the square of the the distance between the charges
4
Q
- How can Coulomb’s Law be described simply?
A
- like charges repel each other
- opposite charges attract each other
5
Q
- What is the formula for Coulomb’s Law?
A
6
Q
- What do each of the components in this formula represent?
A
- R= r1+r2
- it is the distance between the centres of the ions
- k is a constant
- it does not vary across different situations
- Q1 and Q2 are the charges on the ions
- if Q1 is positive and Q2 is negative
- their product will be negative
- we get a negative E
- this just means that the interaction is one of attraction
- if Q1 and Q2 are both either positive or negative
- their product will be positive
- we get a positive E
- this means that the interaction is one of repulsion
7
Q
- What are compounds made up of?
A
- they are made up of atoms or ions that are joined together by chemical bonds
8
Q
- What does Ionic bonding consist of?
A
- it consists of two ions joining together
- it is the force of attraction between negative and positive ions
9
Q
- What does Covalent Bonding consist of?
A
- it involves neutral atoms joining together
10
Q
- What does the electronic configuration of an atom affect?
A
- it affects the chemical behaviour of the atoms
11
Q
- Which group of atoms are chemically stable?
A
- Group 8/8A
- Noble gases
12
Q
- Are Group 8/8A elements chemically inert?
Why?
A
- yes, they are
- they have s2p6 valence shell electrons
- this means that they have a full outer shell (an octet)
- they have no need to either give or take electrons
- this octet shell gives them the stability to have no need to chemically react
13
Q
- What is the Octet Rule?
A
- elements react by either taking or giving electrons until they have a full outer shell (an octet)
AN OCTET= s2p6
14
Q
- Explain how Sodium and Chlorine atoms assist one another in becoming stable?
A
- the Na atoms gives it’s extra electron to the Cl atom
- now both Na and Cl have a s2p6 outer shell configuration
- they have followed the octet rule
- now they are both stable
- Na will become a Na+ ion as it has lost an electron
- Cl will become a Cl- ion as it has gained an electrons
- the two ions are now oppositely charged
- they attract to each other
- all the ions join together to form a large crystal lattice
- this forms the NaCl compound (salt)
15
Q
- What are the Key words for ionic bonding?
A
- transfer of electrons
16
Q
- Explain the process for the Ionic Bonding of Magnesium and Oxygen?
A
- the Magnesium atom has two 3s outermost electrons
- it loses two electrons to gain a s2p6 outer shell electron configuration
- it now has a full n=2 shell
- it has followed the octet rule and is stable
- the Oxygen atom has 6 outermost electrons in the n=2 shell
- it gains two electrons from Magnesium to fill its n=2 shell
- it now has 8 electrons in the n=2 shell
- it has followed the octet rule and is stable
- Mg is now positively charged
- this results in an Mg 2+ ion
- Oxygen is now negatively charged
- this results in an O 2- ion
- through Coulombic attraction of opposite charges
- the Mg 2+ ion is attracted to the O 2- ion
- the 2 + and the 2 - cancel out
- this leaves us with the MgO crystal lattice
17
Q
- Explain the Ionic Bonding that occurs between Magnesium and Chlorine?
A
- the Mg atom needs to shed 2 electrons to have a full n=2 shell
- each Cl atom needs to gain one electron to have a full n=3 shell
- Mg gives one electron to one Cl atom and and another electron to another Cl atom
- this results in the Mg atom becoming an Mg2+ ion
- and the Cl atoms becoming Cl- ions
- this results in the formula: MgCl2
18
Q
- What is a Crystal Lattice?
A
- it is the alternate arrangements of positive and negative ions
- ions are arranged in three dimensions
- ions are crystalline compounds
- there is an ionic bond between the positive and the negative ions
- this arrangement forms a solid crystal (salt)
19
Q
- Between which two elements do ionic bonds form?
A
- between metal and non metals
20
Q
- What does an increase in the number of ions in a solution of water result in?
A
- the water has a higher electrical conductivity
- the electrolytes are stronger
21
Q
- What does the strength of the ionic bonds depend on?
A
- Coulomb’s law
22
Q
- What increases lattice energy?
A
- an increase with the charge on the ions
- a decrease in the size of the ions also leads to an increase in lattice energy
23
Q
- Why is there a decrease in lattice energy from NaF to NaI?
A
- the ionic charges are the same
(Na= +1) (halogens= -1) - the only thing that varies is the distance between the ions
- the halogens increase in size as we go down the group
- the distance (d12) increases as we go down the group
- this leads to the lattice energy (E) decreasing
24
Q
- Why is the lattice energy in MgO four times greater than the lattice energy in NaF?
A
- the charges in MgO are +2 and -2
- the product of these two charges is -4
- the charges in NaF are +1 and -1
- the product of these two charges is -1
- negative 4 is four times greater than negative 1
- therefore the lattice energy will be approximately 4 times greater for MgO than it is for NaF
25
Q
- Read through the summary.
Does everything make sense?
A
- yes
