bonding and structure

Question 1

what is the structure of ionic compounds?

Answer 1

arranged in a giant ionic crystal lattice

held together tightly as oppositely charged ions attract one another strongly

Question 2

name physical properties of ionic compounds (1)

Answer 2

high melting and boiling points

• strong electrostatic forces of attraction between oppositely charged ions
• a large amount of heat energy required to overcome them
• non-volatile

Question 3

name physical properties of ionic compounds (2)

Answer 3

soluble in water

• water molecules are attracted to ions
• weakens the electrostatic force
• ions pulled from solution, dissolve in aqueous solution

insoluble in organic solvents
- no water present, remain tightly held in ionic crystal lattice

Question 4

name physical properties of ionic compounds (3)

Answer 4

conduct electricity in molten and aqueous solution

- free-moving ions in aq solution, cations and anions are free to move and are able to conduct electricity

Question 5

what is the structure of covalent compounds ?

Answer 5

simple molecular structure (SMS)

giant molecular structure (GMS)

Question 6

name physical properties of SMS (1)

Answer 6

low melting and boiling points

• held by weak intermolecular forces of attraction
• can be easily overcome
• volatile

Question 7

name physical properties of SMS (2)

Answer 7

inosluble in water and soluble in organic solvents

Question 8

name physical properties of SMS (3)

Answer 8

do NOT conduct electricity

Question 9

name physical properties of GMS (1)

Answer 9

high meting and boiling points

• large number of atoms held together by strong covalent bonds
• requires a lot of energy to break
• solids at rtp

Question 10

name physical properties of GMS (2)

Answer 10

do NOT conduct electricity ( except graphite )

Question 11

name physical properties of GMS (3)

Answer 11

insoluble in both water and organic solvents

Question 12

diamonds

Answer 12

• covalently bonded to 4 other carbon atoms
• all outer electrons r used for bonding ( CANNOT conduct electricity )
• no free electrons

Question 13

graphite

Answer 13

• covalently bonded to 3 other atoms
• soft and slippery, layers of carbon atoms, slide easily over one another when force is applied
• has one free moving electron that allows it to conduct electricity

Question 14

metallic bonding

Answer 14

• outermost electrons form a sea of delocalised electrons
  surrounding the positive metal ions
• free to move around the metallic lattice structure
• strong electrostatic forces of attraction between positively charged metal ions and negative electrons

Question 15

physical properties of metals (1)

Answer 15

high densities melting and boiling points

- packed tightly in layers and are held by strong metallic bonds

Question 16

physical properties of metals (2)

Answer 16

good conductors of heat and electricity

• outermost electrons break away easily and move freely, mobile electrons allow the metal to conduct electricity
• heat energy is easily transferred within the lattice structure

Question 17

physical properties of metals (3)

Answer 17

malleable and ductile

- can be hammered into diff shapes and drawn into wires without breaking