Section 3 - Period 3 Elements Flashcards Preview

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Flashcards in Section 3 - Period 3 Elements Deck (52)
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1

Is Na or Mg more reactive?

Sodium - it takes less energy to lose one electron than to lose two.

2

How does sodium react with cold water?

- vigorously

- forms alkaline solution

- forms a molten ball on surface

- fizzes and produces Hgas

3

Complete the equation:

2Na(s) + 2H2O(l) --> 

2NaOH(aq) + H2(g) 

4

What is the pH of NaOH?

Strongly alkaline - pH 12-14

5

How does magnesium react with cold water?

- Very slowly

- Alkaline solution is formed

- Thin coating of magnesium hydroxide forms on surface of metal

6

What is the pH of magnesium hydroxide and why?

Weakly alkaline - pH 9-10

It is not very soluble in water so very few hydroxide ions are produced.

7

Complete the equation:

Mg(s) + 2H2O(l) -->

Mg(OH)2(aq) + H2(g)

8

What is a faster way to react magnesium with water and what does it produce?

React it with steam

Magnesium Oxide

9

Complete the equation:

Mg(s) + H2O(g) -->

MgO(s) + H2(g)

10

What do period 3 elements form when they react with oxygen?

Oxides

11

What is the general pattern for oxidation states of elements in oxides? (and what is the exception?)

Usually oxidised to their highest oxidation state (the same as their group numbers).

Sulfur is the exception - it forms SO2 which has an oxidation state of +4. A catalyst and high temp are needed to create SO3

12

Give the equation for:

Sodium and Oxygen

2Na(s) + 1/2O2(g) --> Na2O(s) 

13

Give the equation for:

Magnesium and Oxygen

Mg(s) + 1/2O(g) --> MgO(s)

14

Give the equation for:

Aluminium and Oxygen

2Al(s) + 3/2O2(g) --> Al2O3(s)

15

Give the equation for:

Silicon and Oxygen

Si(s) + O2(g) --> SiO2(s)

16

Give the equation for:

Phosphorous and Oxygen

P4(s) +5O2(g) --> P4O10(s)

17

Give the equation for:

Sulfur and Oxygen

S(s) + O2(g) --> SO2(g)

18

How does Na react in air?

Vigorously

19

How does Mg react in air?

Vigorously

20

How does Al react in air?

Slow (faster if powdered)

21

How does Si react with air?

Slowly

22

How does P react in air?

Spontaneously combusts

23

How does S react in air?

Burns steadily

24

What does the graph of period 3 oxides mpts look like?

(ignore chlorine)

25

Why do the metal oxides (sodium, magnesium and aluminium) have high mpts?

They form giant ionic lattices

Strong forces of attraction between each ion

A lot of energy required to break the bonds

26

Why does MgO have a higher mpt than Na2O?

Mg forms 2+ ions so it bonds more strongly than the 1+ Na ions.

27

Why does Al2Ohave a lower mpt?

The highly charged Al3+ ions distort the oxygen's electron cloud making the bonds partially covalent.

28

Why does SiOhave the highest non-metal oxide mpt?

It has a giant macromolecular structure 

The strong covalent bonds must be broken

This requires a lot of energy

29

Why do the phosphorous and sulfur oxides have relatively low mpts?

They form simple molecular structures 

Weak intermolecular forces (dipole-dipole and VdWs) are easy to break

30

How do you determine if an oxide is acidic or alkaline?

Ionic oxides are alkaline, covalent oxides are acidic.