Group 7

• What are group 7 elements called?

  Halogens
• How many electrons do group 7 elements have in their outer shell?


  7
• Are halogens metals or non metals?


  Nonmetals
• What do halogens consist of?


  molecules made of pairs of atoms
• What happens when chlorine reacts with a metal?


  Ionic compounds are formed e.g. chlorine reacting with sodium forms sodium chloride
• what happens when bromine reacts with a metal e.g. Potassium?


  It forms an ionic compound known as halide, potassium bromine is formed
• What is a compound made between metals and halogens called?

  Halide
• What happens when iodine reacts with a metal e.g. lithium?


  An ionic compounds is formed-Lithium iodide is formed
• What happens when halogens react with non metals?


  Halogens form covalent compounds.
• What happens when chlorine reacts with halogen- a non metal?


  A covalent compound is formed- hydrogen chloride. This is a gas that dissolves in water to form hydrochloric acid
• What happens when bromine reacts with hydrogen- a nonmetal?

  A covalent compound is formed- hydrogen bromide
• What happens when iodine reacts with hydrogen- a nonmetal?


  Hydrogen iodide is formed - a covalent compound
• Why do covalent compounds have lower melting and boiling points compared to ionic compounds?


  Weak intermolecular forces
• Why does relative molecular mass increase down group 7?

  More protons and neutrons in its nucleus as you go down group of halogens
• Why does the melting and boiling point increase down group 7?


  Increasing size of the molecules and the strength of intermolecular forces, as you go down the group meaning more energy is required to overcome these forces
• what happens to reactivity as you go down group 7?


  Decreases
• Why does reactivity decrease down group 7?

  The atoms increase in size, there are more shells, so the outer shell is further away form the nucleus and therefore the electrostatic attraction between the nucleus and the outer shell is weaker so it’s harder to gain an electron to fill the outer shell
• Why does a more reactive halogen displace a less reactive halogen from an aqueous solution of its salt?


  The more reactive halogen has a greater ability to attract and gain electrons
• What are the group 7 elements that are gases at room temperature?


  Fluorine and chlorine
• What are the group 7 elements that are liquid at room temperature?

  Bromine
• What are the group 7 elements that are solid at room temperature?


  Iodine and astatine
• What is fluorine‘s state at room temperature?


  Gas
• What is chlorines‘s state at room temperature?

  Gas
• What is bromines‘s state at room temperature?


  Liquid
• What is iodine‘s state at room temperature?

  Solid
• What colour and state is fluorine at room temperature?


  Gas- yellow
• What colour and state is chlorine at room temperature?


  Gas, yellow-green
• What colour and state is fluorine at room temperature?

  Liquid, red-brown
• What colour and state is iodine at room temperature?


  Solid, grey
• what is the colour of bromine in a dissolved water solution?

  Orange
• what is the colour of chlorine in a dissolved water solution?

  pale green
• what is the colour of iodine in a dissolved water solution?

  Dark brown
• What happens when halogens react with metals?


  Salts are formed
• What happens when group 7 elements react with hydrogen?


  Hydrogen halogens are formed
• What state are hydrogen halides at room temperature?


  Gases
• When hydrogen halides are dissolved in water what is formed?


  Acidic solutions
• What is the chemical symbol for chlorine?

  Cl₂
• What is the chemical formula for potassium chloride?

  KCl
• What is the chemical formula for potassium bromide?

  KBr
• What happens when chlorine is added to potassium bromide?

  Chlorine displaces the bromide ions