Period 3 elements Flashcards
When sodium reacts, how many electrons does it lose?
1
What ion is formed when sodium reacts?
Na+
When magnesium reacts, how many electrons does it lose?
2
What ion is formed when magnesium reacts?
Mg2+
Why is sodium more reactive than magnesium?
It takes less energy to lose one electron as it does 2
How does sodium react with cold water?
Vigourously
What is formed when sodium reacts with water?
Molten ball on the surface, fizzing and H₂ gas
What is the equation for the reaction of sodium with cold water?
2Na(s) + 2H₂O(l) -> 2NaOH(aq) + H₂(g)
What is the pH of the solution formed when sodium reacts with water?
12-14
Strongly alkaline
How does magnesium react with cold water?
Very slowly
What is the pH of the solution formed when magnesium reacts with water?
9-10
Weakly alkaline
Why is the solution formed from the reaction of magnesium and water only weakly alkaline?
Magnesium hydroxide is not very soluble in water, so relatively few hydroxide ions are produced
What is the equation for the reaction of magnesium with cold water?
Mg(s) + 2H₂O(l) -> Mg(OH)₂ (aq) + H₂(g)
Why does magnesium react faster with steam than cold water?
There is more energy
What is the equation for the reaction of magnesium with steam?
Mg(s) + H2O(g) -> MgO(s) + H2(g)
What do period 3 elements form when they react with oxygen?
Oxides in their highest oxidation state (usually)
What is a period 3 elements highest oxidation state?
The same as their group numbers
What is the exception to period 3 elements forming oxides with oxidation states the same as their group number?
Sulfur
Forms SO₂ - oxidation state of 4
What is the equation for the reaction of sodium and oxygen?
2Na(s) + 1/2O₂ -> Na₂O(s)
What is the equation for the reaction of magnesium with oxygen?
Mg(s) + 1/2O₂ -> MgO(s)
What is the equation for the reaction of aluminium with oxygen?
2Al(s) + 1.5O₂ -> Al₂O₃(s)
What is the equation for the reaction of silicon and oxygen?
Si(s) + O₂(g) -> SiO₂(s)
What is the reaction of phosphorus with oxygen?
P₄(s) + 5O₂(g) -> P₄O₁₀(s)
What is the equation for the reaction of sulfur with oxygen?
S(s) + O₂(g) -> SO₂(g)
What is the reaction of Na in air like?
Vigorous
What colour is the flame when Na is burnt?
Yellow
What is the reaction of Mg in air like?
vigorous
What colour is the flame when Mg is burnt?
Brilliant white
What is the reaction of Al in air like?
Slow
What colour is the flame when Al is burnt?
N/A
What is the reaction of Si in air like?
Slow
What colour is the flame when Si is burnt?
N/A
What is the reaction of P in air like?
Spontaneously combusts
What colour is the flame when P is burnt?
Brilliant white
What is the reaction of S in air like?
Burns steadily
What colour is the flame when S is burnt?
Blue
