Basic 7 · Science · Materials
Important Solids and the Periodic Table
In this topic you will discuss the importance of specific solids to human survival, and identify the first twenty elements of the periodic table and their arrangement into metals, non-metals and noble gases.
By the end of these notes you should be able to:
- Identify important solids in the environment and their uses
- Explain how solids support human survival
- Identify the first twenty elements and classify them as metals, non-metals or noble gases
What you already know
- States of matter
Copy everything that has a blue line on its left into your notebook. The other parts are for reading.
Lesson 1
- Strand
- Diversity Of Matter
- Sub-strand
- Materials
- Indicator
- B7.1.1.3 – Discuss the importance of specific solids to life
Introduction
Iron nails hold our roofs together, charcoal cooks our food and clay bricks build our houses. Solids are all around us and many of them are essential for life.
1. Common Solids and Their Uses
| Solid | Source | Uses |
|---|---|---|
| iron and steel | iron ore | nails, roofing, tools, bridges, vehicles |
| wood | trees | furniture, buildings, firewood, paper |
| charcoal | burnt wood | cooking fuel, water filters |
| clay | soil | bricks, pots, tiles |
| stone and gravel | rocks | buildings, roads |
| gold | mines at Obuasi and Tarkwa | jewellery, money reserves, electronics |
| salt | sea water at Ada and Songor | seasoning, preserving fish and meat |
| plastic | crude oil | containers, pipes, chairs |
2. Properties That Make Solids Useful
Solids are useful because of their properties. Iron is strong, so it is used for building. Clay can be moulded when wet and becomes hard when fired. Charcoal burns slowly and gives steady heat. Gold does not rust and is shiny, so it is valuable for jewellery.
3. Minerals from the Earth
Many important solids are minerals mined from the earth. Ghana is rich in minerals: gold (Obuasi, Tarkwa), bauxite (Awaso, Nyinahin), manganese (Nsuta) and diamonds (Akwatia). These minerals provide raw materials and earn foreign exchange, but mining must be done responsibly to protect land and water.
4. Solids in Traditional Crafts
Ghanaian craftspeople have used solids for centuries. Blacksmiths heat and hammer iron into hoes and cutlasses. Potters at Vume and Mpraeso shape clay into pots. Carvers turn wood into stools and drums. Goldsmiths in Kumasi make jewellery and royal regalia. These crafts show how understanding the properties of solids helps people make useful and beautiful objects.
New words
- mineral
- A natural solid substance found in the earth.
- ore
- Rock from which a metal is obtained.
- durable
- Lasting a long time.
- raw material
- A basic substance used to make products.
Summary
- Solids such as iron, wood, charcoal, clay, gold and salt are important to human life.
- Their properties, such as strength and durability, make them useful.
- Ghana has many mineral solids that support the economy.
Class activity: Solids Hunt
- Find ten solids in and around the classroom.
- Record what each is made from and how it is used.
- Present the three most important solids and explain why.
You need: Iron nail, Charcoal piece, Clay brick
Exercises
Answer in your exercise book first, then check your answers.
1. Which solid is used as a cooking fuel?
- A. charcoal
- B. iron
- C. gold
- D. salt
Show answer
Answer: charcoalBurnt wood.2. Bauxite is mined at…
- A. Awaso
- B. Obuasi
- C. Akwatia
- D. Nsuta
Show answer
Answer: AwasoAluminium ore.3. Clay becomes hard when fired.
- A. True
- B. False
Show answer
Answer: TrueUsed for bricks and pots.4. Rock from which a metal is obtained is an ______.
Show answer
Answer: oree.g. iron ore.5. State three uses of iron.
Show answer
Answer: Nails, roofing sheets, tools (or bridges, vehicles).Any three.6. Explain why gold is used for jewellery.
Show answer
Answer: It is shiny, attractive, does not rust and is valuable.Properties.
Lesson 2
- Strand
- Diversity Of Matter
- Sub-strand
- Materials
- Indicator
- B7.1.1.3 – Discuss the importance of specific solids to life
Introduction
Think about a single day. You eat solid food, sleep in a house built of solids, write with a pencil and cook on a stove. Solids meet our most basic needs.
1. Solids and Basic Needs
| Need | Solids that meet it |
|---|---|
| food | rice, yam, cassava, maize, meat, fish, fruits |
| shelter | blocks, bricks, cement, wood, roofing sheets, stones |
| clothing | cotton, leather, synthetic fibres |
| fuel | firewood, charcoal, coal |
| tools | hoes, cutlasses, pots, knives |
| health | tablets, bandages, medical equipment |
2. Solid Foods
Solid foods provide nutrients. Cereals such as maize and rice give energy; legumes such as beans give protein; fruits and vegetables give vitamins and minerals. Many Ghanaian staple foods, such as fufu, kenkey, banku and gari, are made from solid crops.
3. Solids for Shelter and Safety
Houses protect us from rain, sun, wind and dangerous animals. In villages, houses may be built with mud, wood and thatch; in towns, with cement blocks, steel and roofing sheets. Each material has advantages: mud houses are cool and cheap, while cement houses are strong and durable.
4. Using Solids Responsibly
Many solids come from natural resources that can run out or be damaged. Cutting too many trees for firewood and charcoal causes deforestation. Illegal mining destroys farmland and pollutes rivers. We can protect resources by planting trees, using energy-saving stoves, recycling metals and plastics, and supporting legal, responsible mining.
New words
- shelter
- A place that protects from weather and danger.
- staple food
- A main food eaten regularly.
- deforestation
- Clearing large areas of forest.
- natural resource
- A material from nature that people use.
Summary
- Solids provide food, shelter, clothing, fuel, tools and medicines.
- Different building materials have different advantages.
- Natural solid resources should be used responsibly to avoid deforestation and pollution.
Class activity: Survival Solids Chart
- Make a chart of six human needs.
- List solids that meet each need.
- Suggest one way to use each resource responsibly.
You need: Iron nail, Charcoal piece, Clay brick
Exercises
Answer in your exercise book first, then check your answers.
1. Which solid is used for building?
- A. cement block
- B. water
- C. air
- D. milk
Show answer
Answer: cement blockShelter.2. Cutting too many trees for charcoal leads to…
- A. deforestation
- B. irrigation
- C. condensation
- D. recycling
Show answer
Answer: deforestationLoss of forest.3. Fufu is made from solid crops.
- A. True
- B. False
Show answer
Answer: TrueCassava and plantain.4. A place that protects from weather and danger is a ______.
Show answer
Answer: shelterHouse.5. State three human needs met by solids, with an example of each.
Show answer
Answer: Food: rice; shelter: blocks; fuel: charcoal.Any three.6. Compare a mud house and a cement-block house.
Show answer
Answer: Mud houses are cool and cheap but less durable; cement houses are strong and lasting but costly and hotter.Advantages and disadvantages.
Lesson 3
- Strand
- Diversity Of Matter
- Sub-strand
- Materials
- Indicator
- B7.1.1.2.1 – Demonstrate the knowledge of the orderly arrangement of metals non-metals and noble gases in the periodic table
Introduction
All matter is made of about 118 basic substances called elements. Scientists arrange them in a chart called the periodic table, where elements with similar properties are grouped together.
1. What Is an Element?
Element: A pure substance made of only one kind of atom, which cannot be broken down into simpler substances by chemical means.
Each element has a name, a symbol and an atomic number. The atomic number tells the number of protons in its atom and gives the element's position in the periodic table.
2. The First Twenty Elements
| Number | Name | Symbol | Type |
|---|---|---|---|
| 1 | hydrogen | H | non-metal |
| 2 | helium | He | noble gas |
| 3 | lithium | Li | metal |
| 4 | beryllium | Be | metal |
| 5 | boron | B | metalloid |
| 6 | carbon | C | non-metal |
| 7 | nitrogen | N | non-metal |
| 8 | oxygen | O | non-metal |
| 9 | fluorine | F | non-metal |
| 10 | neon | Ne | noble gas |
| 11 | sodium | Na | metal |
| 12 | magnesium | Mg | metal |
| 13 | aluminium | Al | metal |
| 14 | silicon | Si | metalloid |
| 15 | phosphorus | P | non-metal |
| 16 | sulphur | S | non-metal |
| 17 | chlorine | Cl | non-metal |
| 18 | argon | Ar | noble gas |
| 19 | potassium | K | metal |
| 20 | calcium | Ca | metal |
3. Metals, Non-Metals and Noble Gases
In the periodic table, metals are found mainly on the left and in the middle, non-metals on the right, and noble gases in the last column. Metals are usually shiny, conduct heat and electricity and can be hammered into shapes. Non-metals are usually dull, brittle when solid and poor conductors. Noble gases (helium, neon, argon) are very unreactive. Metalloids such as boron and silicon have properties of both metals and non-metals.
4. Remembering the Elements
A memory sentence can help: "Happy Henry Likes Beans Boiled Carefully, Not Over-Fried; Nice Nana Makes Awesome Silky Pepper Soup, Close And Keep Cool" gives H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca.
New words
- element
- A substance made of one kind of atom.
- symbol
- A short code for an element, such as O for oxygen.
- atomic number
- The number of protons in an atom of an element.
- noble gas
- An unreactive gas in the last group of the periodic table.
Summary
- Elements are pure substances arranged in the periodic table by atomic number.
- The first twenty elements run from hydrogen (H) to calcium (Ca).
- Metals are on the left, non-metals on the right and noble gases in the last column.
Class activity: Element Cards
- Make cards for the first twenty elements with name, symbol and number.
- Arrange them in order and sort them into metals, non-metals, metalloids and noble gases.
- Quiz another group on the symbols.
You need: Printed periodic table, Labelled cards for the first 20 elements, Iron nail, Charcoal sample
Exercises
Answer in your exercise book first, then check your answers.
1. The symbol for oxygen is…
- A. O
- B. Ox
- C. Og
- D. Os
Show answer
Answer: OOxygen.2. Which is a noble gas?
- A. argon
- B. sodium
- C. carbon
- D. magnesium
Show answer
Answer: argonElement 18.3. Sodium is a metal.
- A. True
- B. False
Show answer
Answer: TrueElement 11.4. The number of protons in an atom is the ______ number.
Show answer
Answer: atomicPosition in the table.5. Name three metals among the first twenty elements with their symbols.
Show answer
Answer: Sodium (Na), magnesium (Mg), aluminium (Al) (or lithium, potassium, calcium).Any three.6. State two differences between metals and non-metals.
Show answer
Answer: Metals are shiny and good conductors; non-metals are dull and poor conductors (or metals malleable, non-metals brittle).Any two.
Homework
- Learn the names and symbols of the first twenty elements.