QuestionsToRevise(PAPER1)

Simple Covalent Molecules: ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1) Low Melting And Boiling Points (Weak intermolecular forces are easy to overcome) 2) They Do Not Conduct Electricity (there arent any free ions or delocalised electrons) 3) ALSO, Simple Covalent Molecules are Liquid or Gas at Room Temperature ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Graphite is Made of Many Layers of Graphene, Which are Held Together by Weak Intermolecular Forces (which are easy to overcome), So the Layers Can Slide Over Each Other Easily. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ━ ━ Intermolecular Forces = Weak Forces Of Attraction Between Layers Of Graphite

Graphite Conduct Electricity Because: ━ 1) Each Carbon Atom in Graphite has 4 Electrons in its outer Shell ━ 2) 3 Electrons are Used to Form Three Covalent Bonds ━ 3) The Spare 1 Electron in each Carbon Atom is Delocalised and Free to Move Throughout the Structure Carrying Electrical Charge.

Most Giant Covalent Structures are Hard Because Their Atoms are Held Together by Many Strong Covalent Bonds (Which Take Lots of Energy to Break).

Diamond is Hard Because Each Carbon Atom in it Forms Four Strong Covalent Bonds In A Rigid 3D Tetrahedral Structure. ━━━━━━━━━━━━━━━━━━━━━━━━━━━ Diamond Does NOT conduct Electricity because each carbon atom in it forms 4 strong covalent bonds (doesnt leave 1 delocalised like graphite)

Graphene is a Single Layer Of Graphite That is Only One Atom Thick.

Graphene Is: ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Very Strong Has A Very High Melting Point And Conducts Electricity Because It Has Delocalised Electrons. (bc it has 3/4 strong covalent bonds in each carbon atom)

The First Fullerine Discovered was: Buckminsterfullerine ━ Buckminsterfullerine has the Formula C60 and is a Spherical Structure of Carbon Atoms.

Carbon Nanotubes Are Long, Hollow Cylindrical Fullerenes With Tiny Diameters, Made out of Carbon Atoms Arranged in Hexagons. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ • They have High Tensile Strength • They Conduct Heat and Electricity.

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ • Carbon Nanotubes Have Many Strong Covalent Bonds Between Carbon Atoms (which take LOTS of energy to break) ━ • Have a High Length-to-Diameter Ratio

Carbon Nanotubes (Cylindrical Fullerenes) Are Used In: ━━━━━━━━━━━━━━━━━━━━━━━━━━ 1) Nanotechnology 2) Electronics 3) To Strengthen Materials (e.g. Tennis Racket Frames)

Spherical Fullerenes Are Used in: 1) Drug Delivery 2) Lubricants 3) Catalysts Mnemonic: The Spherical Fullerine DLC update

An Alloy Is a Mixture of two or More Metals, or a Metal and Another Element. ━ Alloys are Harder Because they have Different-Sized-Atoms Which Distort the Layers, so they Cannot Slide Over Eachother Easily.

Pure Metals are Malleable Because They Have Regular Layers Of Positively Charged Metal Ions Which Can Slide Over Each Other Easily Without Breaking Metallic Bonds.

Spherical Fullerenes Have Weak Intermolecular Forces Between their Molecules, Allowing the Molecules to Slide Past Each Other Easily Which Reduces Friction Between Surfaces.

Similarities: • Diamond & Graphite Both have a Giant Covalent Structure ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Differences: • Diamond does not Conduct Electricity, due to each Carbon atom having 4/4 Covalent Bonds and no delocalised electrons • Graphite Does Conduct Electricity, due to each Carbon Atom having 3/4 Covalent Bonds (so one spare delocalised electron in each carbon atom) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ • Diamond is Hard (due to strong covalent bonds) • Graphite is Soft & Slippery (due to weak intermolecular forces between layers)

Diamond & Silcon Dioxide Similarities: • Structure: Both are Giant Covalent structures. • Hardness: Both are very Hard with very High Melting Points. (due to strong covalent bonds) • Conductivity: Neither conducts Electricity (no delocalised electrons). ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Diamond & Silcon Dioxide Differences: • Atoms: Diamond is Carbon only; Silicon Dioxide is Silicon and Oxygen. • Bonds: In Diamond, the Carbon atoms have 4 covalent bonds. In Silicon Dioxide, Silicon has 4 covalent bonds but Oxygen has 2.

Giant Covalent Structures: • Structure: Giant Repeating Lattice held together by Strong Covalent Bonds. • Property: High Melting points & Solid at Room Temperature (because lots of energy needed to break strong covalent bonds) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Simple Covalent Molecules: Structure: Small Simple Molecules are held by Weak Intermolecular Forces. • Property: Low melting points & Usually Gas or Liquids at Room Temperature (due to Weak Intermolecular Forces.)

Structure: ━━━━━━━━━━━━━━ Silicon Dioxide has a Giant Covalent Structure with Strong Covalent Bonds Whereas Poly(ethene) has Long Polymer Chains with Weak Intermolecular Forces Between Chains. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Melting Point: ━━━━━━━━━━━━━━━━━ Silicon Dioxide has a High Melting Point due to having Strong Covalent Bonds that Require Large Amounts of Energy to Break. . Whereas Poly(ethene) has a Low Melting Point due to having Weak Intermolecular Forces Between Chains that are Easy to Overcome.

Sodium = 1 Electron on Outershell, but Oxygen is in Group 6 and needs 2 Electrons to be stable. So: ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1) Two Sodium Atoms instead of One react and Lose 1 Electron Each to form two Na⁺ Ions. (hence Na₂O) ━━━━ 2) One Oxygen Atom Gains those 2 Electrons to form an O²⁻ Ion. ━━━━ 3) All Ions Now Have Full Outer Shells and Are Held Together by Strong Electrostatic Forces of Attraction ━━━━ 4) The Formula is Na₂O because 2 (Na⁺) Sodium Atoms Are Needed to Balance 1 O²⁻ Ion (so oxygen gets full outershell of 8)

You Can Separate a Mixture With: 1) Filtration 2) Distillation 3) Chromatography

Filtration Separates an Insoluble (Not Able to Dissolve) Solid from a Liquid ━━━━━━━━━━━━━━━━━━━━━━━━━━ ━ Sand and Water Mixture Example 1) Add filter funnel and filter paper to a beaker 2) Pour mixture into filter funnel 3) Water passes through as filtrate 4) Sand stays on filter paper as residue

Distillation Separates a Liquid by Heating a Mixture so the Liquid with the Lowest Boiling Point Evaportes First, and then that Gas becomes Condensed to a Liquid again in a Cool Condenser. So you have two seperate mixtures now. ━━━━━━━━━━ Condensation = Liquid to Gas

An Isotope Is an Atom OF THE SAME ELEMENT with the Same Number of Protons but a Different Number of Neutrons. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example: carbon-12 and carbon-14. (same elements) They Both have 6 Protons. (but carbon-14 has 2 extra neutrons)