Period 3 elements and their oxides

What does phosphorus and excess oxygen form?

Phosphorous pentoxide

P4 O10

What does sulfur dioxide and water form?

Sulfurous acid

Formula for sulfurous acid

H2SO3

Give the displayed formula for the anion formed when sulfur trioxide reacts with water

EQ

What does excess magnesium and phosphoric acid form?

EQ

Magnesium phosphate

And water

Formula for phosphate ion

Polyatomic ion

PO4 3-

True or false:

Magnesium hydroxide is used to neutralise stomach acid

True

True or false:

Magnesium hydroxide forms a solutio with pH=14 at 25 degrees Celsius

False

Identify a reagent or test that could be used to distinguish between aqueous solutions of sulfur dioxide and sulfur trioxide with the same concentrations

EQ

Reagent-universal indicator

Observation with sulfur dioxide solution- sodium dioxide turns orange red

Observations with sulfur trioxide solution- sulfur trioxide turns red

What does phosphorous oxide with sodium hdyroxide form?

EQ

Sodium phosphate and water

All exam questions first 10

What is formed when phosphorus oxide reacts with water?

EQ

Phosphoric acid

Draw the displayed formula of the molecule formed when phosphorous oxide reacts with water

EQ

In bonding and structure questions you need to talk about what structure they are and the type of intermolecular force there is between all of them

EQ

Why is it dangerous to react sodium in a smaller volume and a smaller reaction vessel?

EQ

Temperature will go up

Formula for phosphorous oxide?

P4 O10

What is formed in the reaction of phosphorous oxide with water

Make an equation

P4O10 + 6 H2O → 4 H3PO4

What type of bonding does silicon dioxide have?

EQ

Covalent bonds

What type of structure is phosphorous oxide

EQ

Simple covalent molecule

What type of bonding does phosphorous oxide have?

EQ

VDW between molecules

What element in period 3 forms an oxide that is insoluble in water?

EQ

Aluminium

Write an equation for the reaction of aluminium oxide with sulfuric acid

EQ

Al2O3 + 3 H2SO4 → Al2(SO4)3 + 3 H2O

Identify the element in period 3 that has the largest atomic radius

EQ

Sodium

Identify the element in period 3 that has the highest electronegativity

EQ

Sodium

What element in period 3 has the highest second ionisation energy

EQ

Sodium

Identify the element in period 3 from sodium to chlorine that has the highest electronegativity

EQ

Chlorine

Give 2 observation when sodium is heated in oxygen

EQ

Yellow flamE

White solid

Observation when phosphorous is heated in oxygen
EQ

White powder

Why is there a greater jump in melting points from sodium oxide to magnesium oxide?

EQ

Greater charge on magnesium ion

Stronger attraction between oppositely charged ions

Comparison of bonds between silicon oxide and phosphorous oxide:

EQ

In silicon oxide they are much stronger than the IMF in P4O10

A sample of the highest oxide of phosphorus was prepared in a laboratory.

Describe a method for determining the melting point of the sample.

State how the result obtained could be used to evaluate its purity.

EQ

Sample in a suitable melting point apparatus

Heat slowly

Range of melting point indicates presenc of impurities

What type of oxide will aluminium form?

EQ

Amphoteric

What type of oxides are magnesium,sodium and sulfur?

EQ

Basic oxides

Describe a test to distinguish between

sodium oxide and P4O10

EQ

Add water

Measure pH

Sodium oxide-12-14

Phosphorous oxide-1-2

State the type of crystal structure shown In sulfur trioxide

EQ

Molecular

Write an equation for the reaction of sulfur trioxide with potassium

hydroxide solution.

EQ

SO3 + 2KOH → K2SO4 + H2O

Write an equation for the reaction of an excess of magnesium oxide with

phosphoric acid

EQ

3 MgO + 2 H3PO4 → Mg3(PO4)2 + 3 H2O

Draw the displayed formula of the undissociated acid formed when sulfur dioxide reacts with water

EQ

What is the formula fo the main aluminium containing species present when aluminium oxide is added to an excess of water

EQ

Al 2O3

Solid

Explain why the melting point of sulfur is greater than that of phosphorous

S8 molecules are bigger than P4 molecules

Allow sulfur molecules have bigger surface area

and sulfur molecules have bigger Mr

1

Therefore, van der Waals / dispersion / London forces between

molecules are stronger in sulf

Explain why sodium oxide forms an alkaline solution when it reacts with

water.

EQ

Sodium oxide contains O2– ions

1

These O2– ions react with water forming OH– ions

Write an ionic equation for the reaction of phosphorus(V) oxide with an

excess of sodium hydroxide soluti

P4O10 + 12OH– 4PO43- + 6H2O

What element has a low melting point as an oxide and dissolves in water to form an acidic solution

EQ

phosphorus

Name an amphoteric oxide

Aluminium oxide

State the meaning of the term amphoteric

Reacts with acids and bases

Write 2 equations to show that aluminium oxide is amphoteric

Al2O3 + 6HCl → 2Al3+ + 6Cl- + 3H2O

Al2O3 + 6H+ → 2Al3+ + 3H2O

Allow equation to form 2AlCl3

Why do both sodium oxide adn magnesium oxide added to water form alkaline solutions

/produce hydroxide ions

Suggest why sodium oxide forms a solution with a higher pH than the

solution formed from magnesium oxide.

sodium hydroxide more soluble than magnesium hydroxide