Starter quiz
- Starting with the first step, sort the following steps into the correct order for conducting a chemical experiment.
- 1⇔Put on safety glasses.
- 2⇔Mix the reactants.
- 3⇔Record any observations.
- 4⇔Clean up your workspace.
- Which element is in Group 7 and Period 3 of the periodic table?
- 'chlorine' ✓
- Which of the following statements correctly describes a salt?
- A substance that turns blue litmus paper red.
- A substance that forms when a metal reacts with a non–metal. ✓
- A substance with a pH greater than 7.
- A substance that does not dissolve in water.
- A substance that is always acidic.
-
- A substance with a pH of 12 is considered to be ...
- acidic.
- alkaline. ✓
- neutral.
- sour.
-
- Which of the following describes a physical change?
- rusting of iron
- melting of ice ✓
- burning of wood
- baking a cake
-
- The process of a substance in the solid state changing directly into the gas state is called ...
- 'sublimation' ✓
Exit quiz
- Which of the following elements is a halogen?
- sodium
- chlorine ✓
- magnesium
- carbon
- oxygen
-
- What happens to the reactivity of the halogens as you go down Group 7?
- increases
- decreases ✓
- stays the same
- fluctuates
-
- The state of iodine at room temperature is ...
- solid. ✓
- liquid.
- gas.
-
- Match the following halogens to their correct description.
- fluorine⇔A pale yellow gas at room temperature. ✓
- chlorine⇔A pale green gas at room temperature. ✓
- bromine⇔A reddish–brown liquid at room temperature. ✓
- iodine⇔A purple–black solid at room temperature. ✓
- Which of the following are products of the reaction between a Group 1 metal and a halogen?
- metal hydroxide
- metal halide ✓
- hydrogen gas
- water
-
- Name the product of the reaction between potassium and bromine.
- 'potassium bromide' ✓
Worksheet
Presentation
Video
Lesson Details
Key learning points
- The elements in Group 7 are all non-metals that have coloured vapours, most of which are toxic.
- The state of the elements at room temperature changes from gas to solid, down Group 7.
- Reactivity decreases down Group 7.
- Halogens react with Group 1 and 2 metals to form metal halides.
- Metal halides are soluble in water.
Common misconception
All halogens are gases at room temperature because they're non-metals; all halogens form toxic compounds.
Not all halogens are gases at room temperature; bromine is a liquid and iodine is a solid. Halogens can be toxic in their elemental form or in high concentrations, but they also form essential compounds, like table salt and disinfectants.
Keywords
Halogen - A halogen is an element found in Group 7 of the periodic table.
Group - A group is a column on the periodic table that corresponds to the number of electrons in the outer shell of an atom.
Halide - A halide is the name of a salt formed from a halogen and another element, e.g., sodium chloride (NaCl).
Salt - A salt is a substance formed when a metal reacts with a non-metal. These reactions typically produce solid substances that can dissolve in water, such as table salt.