Bonding- Chemistry

Question 1

What are ions?

Answer 1

• charged particles
• can be single atoms or groups of atoms

Question 2

When do negative ions form?

Answer 2

• when atoms gain electrons
• they have more electrons than protons

Question 3

When do positive ions form?

Answer 3

• when atoms lose electrons
• they have more protons than electrons

Question 4

What are group 1,2,3 elements?

Answer 4

• metals
• they lose electrons to form positive ions

Question 5

What are group 5,6,7 elements?

Answer 5

• non metals
• gain electrons to form negative ions

Question 6

What do elements in the same group all have?

Answer 6

• the same number of outer electrons
• so they all form ions with the same charge

Question 7

When a group 1 metal and a group 7 non metal react together what happens?

Answer 7

• metal atom loses electrons to form a positive ion
• non metal gains these electrons to form a negative ion

Question 8

What are the oppositely charged ions strongly attracted to each other by?

Answer 8

• electrostatic attraction
• this attraction is called an ionic bond

Question 9

What are ionic compounds made up of?

Answer 9

• positively charged part
• negatively charged part

Question 10

What is the ionic charge of any compound?

Answer 10

• zero
• all the negative charges in the compound must balance all the positive charges

Question 11

How are ions held together in ionic compounds?

Answer 11

• giant ionic structure
• ions are held together in a closely packed 3D lattice arrangement
• by the reaction between oppositely charged ions

Question 12

Why is the electrostatic attraction between oppositely charges ions very strong?

Answer 12

• lot of energy is needed to overcome the strong attraction
• have a high melting and boiling point

Question 13

What does each covalent bond provide?

Answer 13

• one extra shared electron for each atom (sharing pairs of electrons)

Question 14

What is covalent bonding?

Answer 14

• strong electrostatic attraction between the negatively charged shared electrons (the bonding pair) and the positively charged nuclei of the atoms involved

Question 15

How are the molecules in simple molecular substances?

Answer 15

• atoms within a molecule are held together by very strong covalent bonds
• forces of attraction between the molecules are very weak

Question 16

Why are the melting/boiling points are very low for simple molecular substances?

Answer 16

• because the molecules are easily separated

Question 17

Why are intermolecular forces stronger between molecules with a high relative molecular mass than between smaller molecules?

Answer 17

• there are more points along the larger molecules for intermolecular forces to act between them
• so more energy is needed to break the forces

Question 18

What are the properties of giant covalent structures?

Answer 18

• all atoms bonded by strong covalent bonds
• lots of bonds so takes a lot of energy to break them
• so giant covalent are solids with very high melting and boiling points
• insoluble in water
• don’t conduct electricity (not even when in molten)

Question 19

What is diamond made up of?

Answer 19

• network of carbon atoms that each form four covalent bonds

Question 20

Why does diamond have a high melting point?

Answer 20

• strong covalent bonds take a lot of energy to break

Question 21

How are the atoms held in diamond?

Answer 21

• strong covalent bonds hold the atoms in a very rigid lattice structure so its really hard

Question 22

Why does diamond not conduct electricity?

Answer 22

• no free electrons or ions

Question 23

What does each carbon atom form in graphite?

Answer 23

• each carbon atom only forms three covalent bonds creating layers of carbon atoms

Question 24

How are the layers of carbon atoms held together in Graphite?

Answer 24

• held together weakly by intermolecular forces, so are free to slide over each other
• this makes graphite soft and slippery

Question 25

Why has graphite got a high melting point?

Answer 25

• the covalent bonds in the layers need lots of energy to break

Question 26

Why is graphite a non metal that conducts electricity?

Answer 26

• only three out of each carbon’s four outer electrons are used in bonds
• so each carbon atom has one electron thats delocalised and can move

Question 27

What are C60 fullerene molecules?

Answer 27

• hollow spheres made up of 60 carbon atoms
• made up of large covalent molecules

Question 28

What is fullerene held together by?

Answer 28

• intermolecular forces so they can slide over each other
• this means the material is soft

Question 29

Why is fullerene a poor conductor of electricity?

Answer 29

• has one delocalised electron
• however the electrons cant move between the molecules

Question 30

What charge do electrons have?

Answer 30

• negative charge

Question 31

Why don’t solid ionic compounds conduct electricity?

Answer 31

• the ions aren’t able to move around

Question 32

What happens when an ionic compound is dissolved?

Answer 32

• the ions are separate and are able to move in the solution
• this means the compound will conduct electricity

Question 33

What happens when an ionic compound melts?

Answer 33

• ions are also able to move so the compound can conduct electricity

Question 34

What do metals have?

Answer 34

• giant structure of positive ions
• surrounded by sea of delocalised electrons

Question 35

What is metallic bonding?

Answer 35

• the electrostatic attraction between the nuclei of the positive ions and the electrons

Question 36

Why can metals conduct electricity?

Answer 36

• delocalised electrons are able to move through the structure

Question 37

Why are metals good conductors of heat?

Answer 37

• movement of electrons means energy can be transferred quickly through the material

Question 38

Why are metals malleable?

Answer 38

• layers of ions in a metal can slide over each other
• this means they can be hammered or rolled into flat sheets