Group 4 - Unit3.3

Question 1

what causes significant changes in the chemistry of group 4 elements

Answer 1

elements at top = nonmetals
elements at bottom = metallic

Question 2

carbon vs lead
CARBON:

Answer 2

• nonmetal
• form covalent compounds
• stable +4 OS
  (acidic oxides)

Question 3

carbon vs lead
LEAD:

Answer 3

• metal
• form ionic compounds
• stable +2 OS
  (amphoteric oxides, never completely lose acidic character)

Question 4

how do oxidation states change down the group(4)

Answer 4

due to increasing significance of inert pair effect, stability of lower oxidation states increase down the group.

Question 5

most stable oxidation state of Carbon:

Answer 5

+4

Question 6

most stable oxidation state of Silicon

Answer 6

+4

Question 7

most stable oxidation state of Germanium

Answer 7

+4

Question 8

most stable oxidation state of Tin

Answer 8

+4

Question 9

most stable oxidation state of Lead

Answer 9

+2

Question 10

what governs redox properties

Answer 10

stability of oxidation states

Question 11

what is the stablest form of carbon

Answer 11

CO2

Question 12

why is CO a reducing agent

Answer 12

easily oxidised from +2 to +4

Question 13

is tin a reducing agent

Answer 13

yes

Question 14

what is the most stable form of lead

Answer 14

PbO

Question 15

why are all lead(2) compounds oxidising agents

Answer 15

easily reduced
from +4 to +2

Question 16

very strong oxidising agent:

Answer 16

PbO₂

Question 17

what are tetrachlorides

Answer 17

stable chlorides of carbon(CCl₄) and silicon(SiCl₄)

Question 18

what shape are group 4 chlorides

Answer 18

tetrahedral

Question 19

why is there no reaction between CCl₄ and water

Answer 19

massive amounts of energy are needed to break CCl₄ bonds.

Question 20

why is there a reaction between SiCl₄ and water

Answer 20

reacts very quickly in hydrolysis
3d orbitals can accept the lone pairs from H2O to form coordinate bonds.

Question 21

what is the overall equation for SiCl₄ and water

Answer 21

SiCl₄ + 2H₂O –> SiO₂ + 4HCl

Question 22

what do group 4 chlorides look like

Answer 22

white solid

Question 23

what is the most stable form of Pb

Answer 23

Lead Chloride

Question 24

what type of compound is lead chloride

Answer 24

ionic compound

Question 25

does lead chloride react with water

Answer 25

no

Question 26

is lead chloride soluble in water

Answer 26

insoluble

Question 27

are lead(ii) compounds soluble in cold water

Answer 27

all insoluble except Pb(NO₃)₂

Question 28

what does Pb²⁺ and OH⁻ form

Answer 28

white precipitate

Question 29

what does Pb²⁺ and excess OH⁻ form

Answer 29

white precipitate redissolves

Question 30

what does Pb²⁺ and Cl⁻ form

Answer 30

dense white precipitate

Question 31

what does Pb²⁺ and I⁻ form

Answer 31

bright yellow precipitate