Topic 4- Inorganic Chemistry And The Periodic Table

Question 1

What’s the trend in ionization energy down group 2?

Answer 1

Ionization energy decreases:

• as the number of inner shells increases, their force of attraction on the e- being removed decreases.
• as each quantum shell is added, the energy of the outermost electrons increases.
• nuclear charge increases force of attraction increases, IE increases. (This factor is outweighed)

Question 2

What is the trend in reactivity down group two?

Answer 2

General increases because of the decrease in energy required to remove two electrons from each atom of the element.

Question 3

What happens when group two elements react with oxygen?

Answer 3

• when Mg burns in air, bright flame and white solid.
• Ca, Sr, Ba, are heated in air, the reactions are more vigorous.

Question 4

What is the general formula for when a grp2 metal reacts with oxygen.

Answer 4

2M (s) + O2 (g) —> 2MO (s)

Question 5

What happens when grp 2 elements react with chlorine?

Answer 5

• they combine with Cl when heated in the gas.
• More vigorous down the group.

Question 6

What’s the general formula for when grp two elements react with chlorine?

Answer 6

M (s) + Cl2 (g) —> MCl2 (s)

Question 7

What happens when grp two elements react with water?

Answer 7

• very slow, doesnt proceed completely.
• Ca, Br, Ba react with increasing vigor, this can be seen by the increase in effervescence.

Question 8

What happens when group 2 OXIDES react with water?

Answer 8

They form alkali’s
They form colorless solutions

Question 9

What’s the general equation for the reaction of group 2 oxides with water?

Answer 9

MO + H2O -> M(OH)2

Question 10

Explain the trends in solubility of group 2 HYDROXIDES:

Answer 10

Increases down the group (ions get larger, forces holding them together weaken), pH value down the group also increases.
CHARGE DENSITY DECREASES

Question 11

What’s the reaction of group 2 oxides and hydroxides with acids?

Answer 11

They react to form salt and water in a neutralization reaction.

White solid forms colorless solution

Question 12

Explain the trends in solubility of group 2 SULFATES:

Answer 12

Decreases down the group.

MgSO4- soluble
CaSO4- slightly soluble
Sr+BaSO4- insoluble

Question 13

How to test for sulfate ions?

Answer 13

Add a solution containing barium ions, they react to form a white precipitate. But, there must be H+ ions present (nitric or hydrochloride acid) to prevent the barium carbonate from forming as a white parcipitate.

Question 14

What happens when group 2 nitrates and carbonates are heated?

Answer 14

They dont melt- they decompose.

Question 15

What happens when a nitrate ion decomposes?

Answer 15

It can change into nitrite or oxide ion by releasing oxygen gas and/or nitrogen dioxide.

Question 16

What happens when a carbonate ion decomposes?

Answer 16

It can change into an oxide ion by releasing CO2

Question 17

What is the stability of nitrate and carbonate ions influenced by?

Answer 17

The charge and size of cation present.

Question 18

Explain the thermal stability of nitrates

Answer 18

Group 1 and 2 nitrates are white solids.
Decomposes to give NO2 (brown fumes) and / or O2

NO BROWN FUMES- LESSER DECOMPISITION: GROUP 1
Metal nitrate -> metal nitrite + oxygen

BROWN FUMES- GREATER DECOMPOSITION: GROUP 2
Metal nitrate-> metal oxide + nitrogen dioxide + oxygen

Question 19

What can be observed in the decomposition of group 1 and group 2 nitrates?

Answer 19

Group 1- no brown fumes except lithium
Group 2- all brown fumes

Question 20

Explain the thermal stability of carbonates

Answer 20

All group 1 and 2 carbonates are white solids.
Decompose to oxides and gives off CO2

No observation because the gas is colorless

Question 21

What does a high charge density mean for nitrates and carbonates?

Answer 21

Less thermal stable

Question 22

What determines charge density?

Answer 22

Size and charge of ion

Question 23

What is the general trend for MP AND BP in group 7 ?

Answer 23

Depends on the IMF of attraction between the molecules.
Increases down the group

Instantaneous dipole- induced dipole are the forces that exist between halogen molecules.
Force increases as the number of e- and size of e- cloud increases.

Question 24

What is the general trend in reactivity down group 7?

Answer 24

Decreases down the group.

Question 25

Disproportionation for chlorine- formula with water?

Answer 25

Cl2 + H2O -> HCl + HClO

Question 26

Disproportionation of chlorine- with cold alkali?

Answer 26

Cl2 + 2NaOH -> NaCl + NaClO + H2O

Question 27

Disproportionation of chlorine- with hot alkali?

Answer 27

3Cl2 + 6NaOH -> 5NaCl +NaClO3 +3H2O

Question 28

What’s the trend in reducing power for group 7 ions?

Answer 28

Reducing power increases down the group

Question 29

What are the 3 possible products for the partial ionization of sulfuric acid?

Answer 29

1. Sulfur dioxide
2. Sulfur
3. Hydrogen sulfide

Question 30

Write the equation of NaCl with H2SO4 + observations

Answer 30

NaCl + H2SO4 -> NaHSO4 + HCl

HCl - steamy fumes

Question 31

Write the equations of NaBr with H2SO4 + Observations:

Answer 31

1. NaBr + H2SO4 -> NaHSO4 + HBr
   HBr- steamy fumes
2. HBr + H2SO4 -> Br2 + SO2 +2H2O
   Br2- brown fumes. SO2- colorless gas

Question 32

Write the equations of NaI with H2SO4 + observations:

Answer 32

1. NaI + H2SO4 -> NaHSO4 + HI
   HI - steamy fumes
2. 2HI + H2SO4 -> I2 +SO2 + 2H2O
   I2- purple fumes SO2- colorless gas
3. 6HI +H2SO4 -> 3I2 +S + 4H2O
   I2- purple fumes S- yellow solid
4. 8HI + H2SO4 -> 4I2 + H2S +4H20
   I2- purple fumes H2S- potent gas

Question 33

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