Group 7

• What is another name for Group Seven elements?

  Halogens
• What are the characteristics of Group Seven elements?

  • Consist of molecules with two atoms
  • Non-metals
  • Have seven electrons in their outer energy level
• How many electrons do Group Seven elements have in their outer energy level?

  Seven electrons
• Why do atoms of Group Seven elements react with each other?

  To achieve a full outer energy level
• What is a covalent bond?

  • A shared pair of electrons between two atoms
  • Forms molecules consisting of two atoms
• What is the formula for a fluorine molecule?

  $F_2$
• What is the formula for a chlorine molecule?

  $Cl_2$
• How do the melting and boiling points of Group Seven elements change down the group?

  • Melting and boiling points increase as you move down the group
• What physical states are fluorine and chlorine at room temperature?

  Both are gases
• What is the physical state of bromine at room temperature?

  Liquid
• What is the physical state of iodine at room temperature?

  Solid
• Why is iodine a solid at room temperature?

  • Both melting point and boiling point of iodine are higher than 20° C
• What does relative molecular mass indicate about a molecule?

  • Gives an idea of the size of a molecule
  • Increases as you move down Group Seven
• What happens to the relative molecular mass of Group Seven elements as you move down the group?

  It increases
• What are group seven elements also known as?

  Halogens
• Why are group seven elements classified as non-metals?

  Because they are found on the right of the periodic table
• How many electrons do group seven elements have in their outer energy level?

  Seven electrons
• How do group seven elements form covalent compounds with non-metals?

  • They share electrons
  • Form molecules with two atoms
  • Example: Hydrogen chloride (HCl)
• What is the name of the molecule formed by two fluorine atoms?

  Fluorine molecule (F2)
• What type of bond is formed between two non-metal atoms in group seven elements?

  Covalent bond
• What is the process by which halogens form covalent compounds with other non-metals?

  • Halogens and non-metals share electrons
  • Achieve full outer energy levels
  • Form covalent bonds
• What is the compound formed between chlorine and hydrogen called?

  Hydrogen chloride
• What happens when halogens react with metals?

  • They form ionic compounds
  • Halogen gains an electron from the metal
  • Forms negatively charged ions
• What charge does a chloride ion have?

  -1 charge
• What occurs to a chlorine atom when it reacts with lithium?

  It gains one electron and becomes a chloride ion
• What is the overall charge of a chlorine atom after gaining an electron?

  • It has 17 protons and 18 electrons
  • Overall charge is -1
  • Becomes a chloride ion
• What happens to the name of a halogen when it forms an ion?

  The name ends with "ide"
• What is the general behavior of halogens when they react with metals?

  • Gain one electron
  • Form ions with a -1 charge
  • Example: Fluorine becomes fluoride, chlorine becomes chloride
• What are the halogens also known as?

  Group seven elements
• How does the reactivity of halogens change down group seven?

  • Reactivity decreases as you move down the group
  • Fluorine is the most reactive halogen
• What happens when a halogen reacts with a metal?

  A halogen atom gains one electron from the metal
• What is the most reactive element in group seven?

  Fluorine
• Why is chlorine less reactive than fluorine?

  Because of greater distance and increased shielding in chlorine
• What factors contribute to the decreased reactivity of halogens as you move down group seven?

  • Increased distance between outer electrons and nucleus
  • Greater shielding effect from internal electrons
• What is a displacement reaction in the context of halogens?

  A more reactive halogen displaces a less reactive halogen
• What happens when fluorine reacts with sodium bromide?

  Fluorine displaces bromine from sodium bromide
• How do you determine the products of a displacement reaction involving halogens?

  1. Identify the reactivity of the halogens involved
  2. Determine which halogen is more reactive
  3. The more reactive halogen displaces the less reactive one
• What are the products of the reaction between potassium iodide and chlorine?

  Potassium chloride and iodine
• Why does bromine not displace chlorine in a reaction with lithium chloride?

  Bromine cannot displace chlorine due to lower reactivity
• What is the outcome when bromine reacts with lithium chloride?

  No reaction occurs