Chapter 22: Periodicity Flashcards
Reaction of sodium with water.
Vigorous.
Floats, fizzes and melts due to heat released.
Product of sodium with water.
Strongly alkaline sodium hydroxide.
Reaction of magnesium with water.
Slow at room temperature.
Few bubbles of hydrogen formed after few days.
Faster with heated magnesium and steam.
Product of magnesium with steam.
Gives magnesium oxide and hydrogen.
Product of magnesium with water.
Hydrogen and magnesium hydroxide which is sparingly soluble.
Is sodium hydroxide or magnesium hydroxide more alkali?
Sodium hydroxide= pH 13-14
Magnesium hydroxide= pH 10
Are reactions of period 3 elements with oxygen, endothermic or exothermic.
Exothermic.
Reaction of magnesium with air (oxygen).
Strip of magnesium ribbon burns in air with bright white flame.
Product of magnesium with air/ oxygen.
White powder of magnesium oxide.
What happens if burning magnesium is lowered into a gas jar of oxygen?
More intense flame.
Reaction of sodium with air.
Brightly in air to give yellow flame.
Product of sodium with air.
White sodium oxide.
Reaction of aluminium with air and has jar of oxygen.
Burns brightly.
Product of aluminium in air.
Aluminium oxide.
What is aluminium covered in as it is reactive metal?
Strongly bonded surface layer of oxide.
Why is aluminium covered in strongly bonded surface layer of oxide?
Protects from further reaction.
Name some everyday uses for aluminium.
Saucepans, window frames, garage doors.
When will silicon form an oxide?
If heated strongly in oxygen.
What must be done to red phosphorous before it can be reacted with oxygen?
Must be heated.
What is given off when white phosphorus ignites in air?
White smoke of phosphorous pentoxide.
What is the difference between red and white phosphorous?
White phosphorus spontaneously ignites in air.
Red and white phosphorus are … of phosphorus.
Allotropes.
What are allotropes?
Same element with atoms arranged differently.
When phosphorus burns, if oxygen is limited, what is also formed?
Phosphorous trioxide.
P2O3
What happens when sulphur powder is heated and lowered into a gas jar?
It burns with a blue flame to form colourless sulphur dioxide and a little sulphur trioxide.
What is the bonding in aluminium?
Both ionic and covalent character.
Why does aluminium show both covalent and ionic character?
Aluminium forms a very small ion with a large positive charge and so can approach closely to the O2- and distort its electron cloud.
How is it possible to predict ionic character of a bond?
Look at the difference in electronegativities.
The greater the difference= Greater the ionic character.
What bonds are present in phosphorous oxides?
van dear Waals
Dipole-dipole
As you move across the period, the solutions of the oxides go from … to …
Alkali
Acidic
What do sodium oxide and magnesium oxide react with? And what is formed?
React with acids.
Forms salt and water.
What does aluminium oxide react with and what is this called?
Both acids and alkalis.
Called an amphoteric oxide.
What does silicon dioxide react with?
Strong bases as it acts as a weak acid.
