Unit 3.5.2 - Periodicity Flashcards
What is the equation for the reaction between aluminium oxide and H₂SO₄?
Al₂O₃(s) + 3H₂SO₄(aq) → Al(SO₄)₃(aq) + 3H₂O(l)
Why is sodium more reactive than magnesium?
Because it takes less energy to lose one electron than it does tow, so more energy (usually heat) is needed for magnesium to react
Why can aluminium oxide be classed amphoteric?
They neutralise acids or bases
What is the equation for the reaction between phosphorus oxide and water?
P₄O₁₀(s) + 6H₂O(l) → 4H₃PO₄(aq)
Does silicon dioxide react with water?
No it is insoluble
What are period 3 elements usually oxidised too? However what is the expectation to this?
Their highest oxidation state, sulphur as it only goes to a +4 state
How fast is the reaction with aluminium and air?
Slow
What is the equation for the reaction between magnesium and oxygen?
Mg(s) + ¹/₂O₂(g) → MgO(s)
What is the equation for the reaction between silicon and oxygen?
Si(s) + O₂(g) → SiO₂(s)
Which of the period 3 oxides dissolve in water to form hydroxides?
Na and Mg
What is the equation for the equation between phosphorus oxide and NaOH?
P₄O₁₀(s) + 12NaOH(aq) → 4Na₃PO₄(aq) + 6H₂O(l)
Why do phosphorus oxide and sulphur dioxide have relatively low melting points?
They form simple molecular structures and so there is only weak intermolecular forces between the molecules which are easy to overcome and so take less energy meaning they have quite a low melting point
What can aluminium oxide be classed as?
Amphoteric
What is the equation for the reaction between sulphur trioxide and water?
SO₃(l) + H₂O(l) → H₂SO₄(aq
What is the equation for the equation between sulphur trioxide and NaOH?
SO₃(g) + 2NaOH(aq) → Na₂SO₄(aq) + H₂O(l)
What colour flame is produced when you burn sodium in air?
Yellow
What do period 3 elements form when they react with oxygen?
Element oxides
How does magnesium react with water?
It reacts very slowly with cold water, you can’t see any reaction is taking place, H₂ gas and Mg(OH)₂ is produced
What is the equation for the reaction between sodium oxide and water?
Na₂O(s) + H₂O(l) → 2NaOH(aq)
Why can silicon, phosphorus and sulphur oxides be classed as acidic?
They can neutralise bases
What is the equation for the reaction between sulphur dioxide and water?
SO₂(g) + H₂O(l) → H₂SO₃(aq)
What ions does sodium produce when it reacts with water?
Na⁺
How fast is the reaction between sulphur and air?
It burns steadily
Why do the metal oxides in period 3 have high melting points?
There are strong forces of attraction between the oppositvely charged ions which means it takes a lot of heat energy to break the bonds and melt them
What test can you do do identify the period 3 element?
The flame test
Is sodium or magnesium more reactive with water?
Sodium
What colour flame is produced when you burn magnesium in air?
Brilliant white
What is the equation for the reaction between sulphur and oxygen?
S(s) + O₂(g) → SO₂(g)
What is the equation for the reaction between sodium and water?
2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)
Why does the reaction between sodium and water produce an alkaline solution?
Because NaOH is formed
What can sodium and magnesium oxide be classed as?
Basic
What colour flame is produced when you burn phosphorus in air?
Brilliant white
How fast is the reaction with sodium and air?
Vigorous
Which metal oxide in period 3 has the highest melting point and why?
Magnesium forms 2+ ions which attracts the oxygen ions more strongly than 1+ ions
What is the equation for the equation between sulphur dioxide and NaOH?
SO₂(g) + 2NaOH(aq) → Na₂SO₃(aq) + H₂O(l)
What are the two period 3 elements you have to know about for their reaction with water?
Sodium and magnesium
Why is the solution formed when magnesium reacts with water less alkaline than when sodium reacts with water?
Mg(OH)₂ isn’t very soluble in water and so not many hydroxide ions are produced, meaning the solution is only weakly alkaline
Which three period 3 oxides have the highest melting point?
Sodium oxide, magnesium oxide and aluminium oxide
How fast is the reaction with silicon and air?
Slow
Which elements from period 3 readily react in air?
The more reactive metals so Na and Mg and the more reactive non metals so P and S
What is the equation for the reaction between sodium and oxygen?
2Na(s) + ¹/₂O₂(g) → Na₂O(s
What is the equation for the equation between silicon dioxide and NaOH?
SiO₂(s) + 2NaOH(aq) → Na₂SiO₃(aq) + H₂O(l)
What ion does magnesium produce when it reacts with water?
Mg²⁺
What is the equation between magnesium oxide and H₂SO₄?
MgO(s) + H₂SO₄(aq) → MgSO₄(aq) + H₂O(l)
How fast is the reaction between phosphorus and air?
It spontaneously combusts
What two period 3 elements don’t produce a flame when burnt?
Aluminium and silicon as they react very slowly
How does sodium react with cold water?
It reacts vigorously with cold water, forming a molten ball on the surface, fizzing and producing H₂ gas and NaOH
What pH is the solution after sodium reacts with water?
pH 12-14
What colour flame is produced when you burn sulphur in air?
Blue
What is the equation for the reaction between phosphorus and oxygen?
P₄(s) + 5O₂(g) → P₄O₁₀(s)
What is the equation between sodium oxide and HCl?
Na₂O(s) + 2HCl(aq) → NaCl(aq) + H₂O(l)
Why can sodium and magnesium oxide be classed as basic?
They can neutralise acids
How fast is the reaction with magnesium and air?
Vigorous
Which of the period 3 oxides dissolve in water to form acidic solutions?
Phosphorus oxide, sulphur dioxide and sulphur trioxide
What is the equation for the reaction between magnesium oxide and water?
MgO(s) + H₂O(l) → Mg(OH)₂(aq)
What can silicon, phosphorus and sulphur oxides be classed as?
Acidic
Which non metal in period 3 has the highest melting point?
Silicon dioxide - it has giant macromolecular structure, so there are covalent bonds in all directions holding the structure together so lots of energy is needed to break the bonds and so the melting temperature is higher
What pH are the solutions formed when the simple covalent oxides of the period 3 non-metals react with water?
pH 0-2
What pH is the solution formed when magnesium reacts with water?
pH 9-10
What is the equation for the reaction between magnesium and water?
Mg(s) + 2H₂O(l) → Mg(OH)₂(aq) + H₂(g)
What is the equation for the reaction between aluminium oxide and NaOH?
Al₂O₃(s) + 2NaOH(aq) + 3H₂O(l) → 2NaAl(OH)₄(aq)
Draw a graph which shows the trend in the melting point of the period 3 oxides.
What can you use to make magnesium react faster?
Steam
Name the eight elements in period 3.
Sodium, magnesium, aluminium, silicon, phosphors, sulphur, chlorine and argon
What number row in the periodic table is period 3?
Third row
What is the equation for the reaction between aluminium and oxygen?
2Al(s) + 1¹/₂O₂(g) → Al₂O₃(s)
Why is NaOH more alkaline than Mg(OH)₂?
Sodium hydroxide is more soluble it will form a more alkaline solution than magnesium hydroxide
Which metal oxide in period 3 has the lowest melting point and why?
Aluminium oxide because the 3+ ions distort the oxygen’s electron cloud making the bonds partially covalent and so weaker
