Chem

• What is the focus of the video discussed?

  Ed EXL GCSE Chemistry Paper 2
• Why is the periodic table called 'periodic'?

  Similar properties occur at regular intervals
• What are the columns in the periodic table called?

  Groups
• What are the rows in the periodic table called?

  Periods
• What do elements in the same group have in common?

  Same number of electrons in outer shell
• How many electrons do group one elements have in their outer shell?

  One electron
• How many electrons do group two elements have in their outer shell?

  Two electrons
• How does the reactivity of group one metals change down the group?

  Reactivity increases down the group
• Why does reactivity increase down group one metals?

  Atoms increase in size and more shells
• What happens to the electrostatic attraction as you go down group one?

  It becomes weaker
• What is the general reaction of group one metals with water?

  Metal plus water makes metal hydroxide plus hydrogen
• What do alkaline metals form when they react with water?

  Metal hydroxide and hydrogen gas
• What is observed when alkaline metals react with water?

  Fizzing and solid metal disappearing
• What group are halogens found in the periodic table?

  Group seven
• How many electrons do group seven elements have in their outer shell?

  Seven electrons
• What type of molecules do halogens consist of?

  Diatomic molecules
• How does the reactivity of group seven elements change down the group?

  Reactivity decreases down the group
• Why does reactivity decrease down group seven?

  Atoms increase in size and more shells
• What happens to the melting and boiling points of halogens down the group?

  They increase down the group
• Why do melting and boiling points increase down group seven?

  Molecules increase in size, stronger intermolecular forces
• What are the states of halogens at room temperature?

  • Fluorine: gas, yellow
  • Chlorine: gas, yellow-green
  • Bromine: liquid, red-brown
  • Iodine: solid, gray
• What do halogens produce when they react with metals?

  Salts
• What do halogens form when they react with hydrogen?

  Hydrogen halides
• What happens when chlorine reacts with potassium bromide?

  Chlorine displaces bromine
• What happens when chlorine reacts with potassium fluoride?

  No reaction occurs
• What is observed when potassium bromide reacts with chlorine?

  Orange color from bromine solution
• What is the test for chlorine gas?

  Damp blue litmus paper turns white
• What are spectator ions?

  Ions that do not change during a reaction
• What is the balanced displacement reaction of chlorine and potassium bromide?

  Cl₂ + 2 KBr → 2 KCl + Br₂
• What are the properties of group zero elements?

  Full outer shell, unreactive, monatomic
• How does the boiling point of group zero elements change down the group?

  Boiling point increases down the group
• What is helium used for due to its properties?

  Used in balloons and airships
• Why is argon used as a shield gas in welding?

  It prevents oxidation of metals
• What is the definition of the rate of a reaction?

  Measurement of how quickly reactants are used
• How do you calculate the mean rate of a reaction?

  Quantity of reactant or product divided by time
• What are the units for rate of reaction when measuring mass?

  Grams per second
• What are the units for rate of reaction when measuring volume?

  cm³ per second
• What does a steep curve on a reaction rate graph indicate?

  High rate of reaction
• What does a shallow curve on a reaction rate graph indicate?

  Low rate of reaction
• What is the method for measuring change in mass during a reaction?

  Use a balance and record at intervals