C2 Flashcards
Describe in terms of electrons what happens when magnesium reacts with oxygen to form magnesium oxide (4)
One magnesium atom loses 2 electrons to form a positive magnesium ion.One oxygen atom gains 2 electrons to form a negative oxide ion. Ionic bonds are formed between the negative oxide ion and the positive magnesium ion to form magnesium oxide.
Describe the structure of magnesium sulfide using giant ionic lattice.
The giant ionic lattice consists of a positive magnesium ion and a negative sulfide ion. There are strong electrostatic forces of attraction because these ions are oppositely charged meaning that a lot of energy is required to break these forces down.
Whqt is a covalent bond
A pair of electrons shared between 2 non metal atoms to form strong covalent bonds which create molecules.
Why do simple covalent molecules have a low melting and boiling point
Bcs not a lot of energy is required to break the weak intermolecular forces between them.
Do SI.ple covalent molecules conduct electricity?
No bcs the electrons are not delocalised and therefore aren’t able to move freely and carry charge
Explain why oxygen is a gas at room temperature, but potassium
Oxide is a solid at room temp(6)
Bcs oxygen is an example of a simple covalent molecule with weak intermolecular forces of attraction. This means that not a lot of energy is required to overcome these forces of attraction.Therefore the oxygen molecules will have a low BP and will.be a gas at room temperature.WHEREAS,potassium oxide is an example of an ionic compound with strong electrostatic forces of attraction between the Potassium oxide ions .This means that a lot of energy is required to overcome these strong electrostatic forces therefore sodium chloride will be a solid at room temp due to its high melting point.
Explain why metals have a high melting point
Bcs the metals are in a giant lattice structure, meaning that they have strong forces of attraction between the metal ions. Therefore a lot of energy is required to overcome these forces of attraction and will therefore have a high melting point and be a solid at room temp
Why can metals conduct electricity and conduct thermal energy
Electricity- because the delpcalised electrons can move freely through the structureand carry charge.
Thermal energy- because the delocalised electrons can move freely through the surroundings and transfer thermal energy.
Explain y alloys are harder than pure metals (eg. Magnalium(ALLOY) with Magnesium and allumium)
Bcs the different sized atoms disrupt the structure and the layers can not slide over each other, which makes magnalium hard.
