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SIM 1
Subject : Chemistry Type of Lesson: Lecture and Demonstration
Grade : 10 CSEC OBJ: Students should develop or determine an order of reactivity of the metals.
Term:^3 UNIT: Reactivity of Metals
Duration: 80 minutes^ Lesson:^1
Week: 1
Objectives
As a result of this lesson, you will be able to:
- discuss the reactivity of metals.
- state the products formed when metals react with oxygen.
- state the products formed when metals react with water or steam.
- state the products formed when metals react with dilute acids.
Prerequisite Student Knowledge
You should be familiar with:
- Metals as elements that react by losing electrons to form ions.
- Metals as elements found mainly to the left of the Periodic Table in the first three groups.
- Some reactions of metals.
- The terms acidic and basic.
Important Points
Important points in this lesson:
- Some metals are unreactive and others are very reactive.
- The reactivity of a metal can determined from its position in the Periodic Table.
- Metals can undergo reactions with oxygen, water and dilute acids.
Key Terms
Reactivity Valency Electropositive
Amphoteric
Challenge Areas
- Does water react with (i) Sodium (ii) Magnesium? In each case, if a reaction occurs, state the conditions required and name the products formed.
- Use the following elements to answer the questions below: aluminium, bromine, calcium, chlorine, hydrogen, iodine, iron, magnesium, nitrogen, oxygen. Each element can be used once, more than once, or not at all.
Name an element which: (a) Forms two different positive ions (b) Has an amphoteric oxide (c) Is the most reactive in the list
Equipment/Material Needed
Basin of water, small piece of sodium, magnesium ribbon, tongs, Bunsen burner, dilute sulphuric acid, dilute hydrochloric acid, boiling tube of boiling water, zinc, calcium, iron, lighted splint.
Note to Student
While the teacher is performing the demonstrations, carefully observe the techniques for heating solids, trapping gases and working with dilute acids.
Body of Lesson
1) Discussion - Reactivity of metals.
a. Your teacher will discuss the following points:
i. Metals are generally defined as elements which can form ions by electron loss. The number of electrons lost per atom is the valency of the metal and the ion carries an equal number of positive charges. Metals are therefore described as electropositive.
ii. This ionization behaviour of metals results in important chemical properties of metals. The first chemical property is the reaction of metals with oxygen in the air. This results in the formation of a metallic oxide.
2) Demonstration – Reactions of metals.
a. Your teacher will demonstrate the burning of magnesium ribbon in air.
i. What product is formed? ii. Write a balanced chemical equation for the reaction when magnesium is heated in oxygen. iii. You may also visit the following link to observe this reaction. http://www.s-cool.co.uk/gcse/chemistry/metals- -the-reactivity-series/reactions-of-metals.html
Click on the video clip of the reaction of magnesium in oxygen.
iv. Note carefully all the changes the magnesium ribbon undergoes. Do you know the name of the substance formed? Magnesium when heated in oxygen from air produces magnesium oxide. If the oxide formed is soluble in water then an alkaline solution is formed (pH greater than 7). Some metals such as zinc, aluminium and lead form amphoteric oxides. This means that these oxides react with both acids and alkalis.
Write the word equation for the reaction in your book and confer with your classmates for a consensus.
b. The second chemical property is the reaction of metals with water. Most metals react with water to form the hydroxide and hydrogen gas or with steam to form the oxide and hydrogen gas.
c. Your teacher will demonstrate the reaction of a tiny piece of sodium in a large basin of water or you may visit the following link to watch this reaction. http://www.s-cool.co.uk/gcse/chemistry/metals-- the-reactivity-series/reactions-of-metals.html
Click on the video clip showing the reaction of sodium with water. You may also want to observe the reaction with calcium and water.
d. Write the chemical equation for the reaction of:
i. sodium and water and
ii. zinc and steam
e. Metals also react with dilute acids by displacing the hydrogen ion in acids to form salts and hydrogen. Your teacher will demonstrate the reaction of calcium with dilute sulphuric acid and iron with dilute hydrochloric acid. You may visit the following link to watch a demonstration of the reaction of an acid with a metal. Carefully observe the correct method of trapping and testing the gas to confirm it is hydrogen.
http://www.s-cool.co.uk/gcse/chemistry/metals-- the-reactivity-series/reactions-of-metals.html
i. Write the chemical and ionic equations for the reactions of: (a) calcium and dilute sulphuric acid and (b) iron and dilute hydrochloric acid in their notebooks.
f. Answer the following question:
Reactivity the relative capacity of an atom, molecule, or radical to undergo a chemical reaction with another atom, molecule, or compound.form new compounds.
CSEC Questions
- Describe three different chemical properties of metals, using a different metal to illustrate each property (equations are essential).
- June 2006, question 4 part a(i) – (ii) inserted below
Recommended Materials
Video clip showing reaction of sodium with water, video clip showing reaction of magnesium in oxygen, video clip showing reaction of calcium with dilute HCl. http://www.s- cool.co.uk/gcse/chemistry/metals--the-reactivity-series/reactions-of- metals.html
Bibliography
Tindale Anne (1998), Chemistry: A concise revision course for CXC, Stanley Thornes Ltd.
Holderness & Lambert (1992), A New Certificate Chemistry, 8th Edition, Heinemann Educational Books.
