Save My Exams bonding

Question 1

Changes of state

Answer 1

physical changes that are reversible
do not change the chemical properties or chemical makeup of the substances involved

Question 2

Evaporation

Answer 2

he change of liquid to gas, but unlike boiling, evaporation occurs only at the surface and takes place at temperatures below the boiling point

Question 3

Boiling

Answer 3

occurs at a specific temperature and takes place when the vapour pressure reaches the external atmospheric pressure

Question 4

Between 1 & 2 on change of state graph

Answer 4

the particles are vibrating and gaining kinetic energy and the temperature rises

Question 5

Between 2 & 3

Answer 5

all the energy goes into breaking bonds – there is no increase in kinetic energy or temperature

Question 6

Between 3 & 4

Answer 6

particles are moving around and gaining in kinetic energy

Question 7

Between 4 & 5

Answer 7

the substance is boiling, so bonds are breaking and there is no increase in kinetic energy or temperature

Question 8

5 & 6

Answer 8

particles are moving around rapidly and increasing in kinetic energy

Question 9

Ionic bonding

Answer 9

the transfer of electrons from a metallic element to a non-metallic element
Transferring electrons usually leaves the metal and the non-metal with a full outer shell
formed between the oppositely charged ions, which occurs in all directions

Question 10

Electrostatic attractions

Answer 10

formed between the oppositely charged ions to form ionic compounds

Question 11

ions form a

Answer 11

lattice structure which is an evenly distributed crystalline structure
regular repeating pattern so that positive charges cancel out negative charges
Each ion is attracted to all of the oppositely charged ions around it
Therefore the final lattice is overall electrically neutral

Question 12

Covalent bonding

Answer 12

occurs between two non-metals
A covalent bond involves the electrostatic attraction between nuclei of two atoms and the bonding electrons of their outer shells
No electrons are transferred but only shared

Question 13

how many electrons shared in single carbon bond

Answer 13

2

Question 14

how many electrons shared in double carbon bonds

Answer 14

4

Question 15

how many electrons shared triple carbon bonds

Answer 15

6

Question 16

expanding the octet rule’

Answer 16

Being able to accommodate more than 8 electrons in the outer shell

Question 17

electron deficient’

Answer 17

Accommodating less than 8 electrons in the outer shell means than the central atom is ‘electron deficient’

Question 18

Dative Covalent Bonding

Answer 18

Some molecules have a lone pair of electrons that can be donated to form a bond with an electron-deficient atom
An electron-deficient atom is an atom that has an unfilled outer orbital
So both electrons are from the same atom
This type of bonding is called dative covalent bonding or coordinate bonding

Question 19

In a dot and cross diagram:

Answer 19

Only the outer electrons are shown
The charge of the ion is spread evenly which is shown by using brackets
The charge on each ion is written at the top right-hand corner

Question 20

Ionic compounds

Answer 20

Ionic bonds are formed when metal atoms transfer electrons to a non-metal to form a positively charged and negatively charged ion
The atoms achieve a noble gas configuration

Question 21

Covalent compounds

Answer 21

The atoms in covalent compounds will share their outer valence electrons to achieve a noble gas configuration

Question 22

Metallic Bonding

Answer 22

tightly packed together in lattice structures
electrons in their outer shells are free to move throughout the structure
‘delocalised electrons’
When the electrons are delocalised, the metal atoms become positively charged ions
The positive charges repel each other and keep the neatly arranged lattice in place
There are very strong forces between the positive metal centres and the ‘sea’ of delocalised electrons

Question 23

Giant ionic lattices

Answer 23

When an ionic compound is formed, the attraction between the ions happens in all directions
Ionic compounds are arranged in giant ionic lattices (also called giant ionic structures)
The type of lattice formed depends on the sizes of the positive and negative ions which are arranged in an alternating fashion
The ionic lattice of MgO and NaCl are cubic

Question 24

Covalent lattices

Answer 24

Covalent compounds can be arranged in simple molecular or giant molecular lattices
Simple molecular lattices: iodine, buckminsterfullerene (C60) and ice
Giant molecular: silicon(IV) oxide, graphite and diamond

Question 25

Graphite, diamond and buckminsterfullerene are all

Answer 25

allotropes of carbon; they are different structural forms of the same element (which is carbon).

Question 26

giant metallic lattice

Answer 26

metal ions are surrounded by a ‘sea’ of delocalised electrons
packed in hexagonal layers or in a cubic arrangement

Question 27

alloy

Answer 27

If other atoms are added to the metal structure, such as carbon atoms, this creates an alloy
Alloys are much stronger than pure metals, because the other atoms stop the layers of metal ions sliding over each other easily

Question 28

strength of the metallic attraction can be increased by:

Answer 28

Increasing the number of delocalised electrons per metal atom
Increasing the positive charges on the metal centres in the lattice
Decreasing the size of the metal ions

Question 29

properties of metallic compounds

Answer 29

1)HIGH M+B
2)good conductors
3)malleable and ductile

Question 30

high m+b metallic

Answer 30

strong metallic bonds
large amounts of heat energy needed to over come and break bonds

Question 31

good conductors metallic

Answer 31

free electrons
move and carry charge

Question 32

maleable and ductile metallic

Answer 32

layers of positive ions sliding over each other

Question 33

Simple covalent lattices have low melting and boiling points

Answer 33

These compounds have weak intermolecular forces between the molecules
Only little energy is required to break the lattice

Question 34

Most compounds are insoluble with water

Answer 34

They do not conduct electricity in the solid or liquid state as there are no charged particles

Question 35

Giant covalent lattices have very high melting and boiling points

Answer 35

These compounds have a large number of covalent bonds linking the whole structure
A lot of energy is required to break the lattice

Question 36

Graphite is soft

Answer 36

the forces between the carbon layers are weak
Diamond and silicon(IV) oxide are hard as it is difficult to break their 3D network of strong covalent bonds

Question 37

Metallic structures are malleable

Answer 37

When a force is applied, the metal layers can slide
The attractive forces between the metal ions and electrons act in all directions
So when the layers slide, the metallic bonds are re-formed
The lattice is not broken and has changed shape