This chapter introduces the basic building blocks of matter and some of the important group schemes researchers use to communicate around matter. Among the main challenges of this introduction (and this is true at every levels) is the learners room easily puzzled by the terminology. "Atom" is often perplexed with "molecule" and the difference between element and also compound is likewise one that learners find difficult to make. For this reason, these concepts and also their explanations are repeated very often transparent the chapter. Us have additionally included plenty of diagrams of what the different classes of matter would look like at the atomic/molecular scale. Due to the fact that these atoms and molecules space too small to see even with a microscope, scientific research educationists usage the adjective "sub-microscopic" to describe diagrams that depict entities on this scale. The ability to imagine chemical occasions as castle would occur on the sub-microscopic range lies in ~ the heart of knowledge chemistry and also the prominence of developing this ability cannot it is in overstated.

You are watching: A pure substance made up of the same kind of atoms is called

that is equally necessary for learners to have the ability to interpret and also draw sub-microscopic diagrams. We have additionally built in tasks where learners need to construct molecules making use of plasticine or pat dough, come reinforce the skill. Pat dough is easy and cheap to make; a recipe follows.

Play dough recipe


2 cup flour 2 cups warmth water 1 cup salt 2 tablespoons vegetables oil 1 tablespoon cream of tartar (optional for improved elasticity) food colouring in different colours


Mix every one of the ingredients together and also stir over low heat. The dough will start to thicken until it each other mashed potatoes. As soon as the dough pulls far from the sides and also clumps in the center of the pan, eliminate the pan from the heat and enable the dough come cool sufficient to handle. Note: If the dough is tho sticky, it merely needs to it is in cooked longer. Revolve the dough the end onto a clean surface and knead vigorously until smooth. Division the dough right into balls for colouring. Make a small depression in the center of the ball, and pour a tiny food colouring right into it. Occupational the colour with the dough, adding an ext if you wish to rise the soot of the colour.

1.1 The building blocks of issue (1 hour)




Activity: A quick revision of the regular Table the Elements

Accessing and also recalling information, sorting and also classifying, writing

Suggested (optional revision)

1.2 Sub-atomic particles (1.5 hours)




Activity: Make her own design of one atom

Reading, interpreting, accessing and also recalling, making, drawing, labelling, communicating

CAPS suggested

1.3 Pure building material (3 hours)




Activity: Studying depictions of atoms and also elements

Accessing and recalling information, interpreting, reading, writing


Activity: Atoms and also molecules

Accessing and also recalling information, revising


Activity: Writing and understanding straightforward chemical formulae

Accessing and also recalling information, interpreting, sorting and also classifying, reading, writing, making, drawing, communicating

CAPS suggested

Activity: Imagining the decomposition that water in ~ the range of molecules

Accessing and recalling information, interpreting, sorting and classifying, making, writing,


Investigation: The decomposition the copper chloride

Observing, record information, interpreting,

CAPS suggested

1.4 mixtures of elements and compounds (0.5 hours)




Activity: Distinguishing in between elements, compounds and mixtures

Sorting and classifying,


What is matter comprised of, in ~ the most an easy level? What do elements look favor at an atomic level? how are the atom of one facet different indigenous the atoms of another element? i beg your pardon table summarises every the aspects known to mankind according to your chemical properties? room atoms the smallest particles making up matter, or are they themselves made up of also smaller particles? What execute scientists know about the "inside" the the atom? Why execute we to speak atoms room "neutral"? once is a problem "pure"? how is a compound various from an element? just how is a molecule different from one atom? What holds molecules together? What happens to atoms and molecules throughout a chemistry reaction? just how is a mixture of facets different from a compound?

What is matter? The traditional an interpretation says matter is noþeles that has mass and also occupies volume (takes up space).

We could say that issue is "stuff", however that would not be really specific. To know matter in a scientific way, we need to imagine what it is make of.

every the different varieties of issue that exist on planet are made up of one or an ext chemical elements. Girlfriend were introduced to few of the aspects in Gr. 7 Matter and Materials. Prior to reading further, stop and see just how much you deserve to remember around the elements. Write down what girlfriend remember or speak it out loud.

there are much more than 100 recognized elements and scientists space still in search of more. We additionally learnt that each facet has a distinct name, chemical symbol and atomic number the represents it, in addition to a fixed place on the periodic Table that elements.

The title of this section is "The building blocks the matter". For this reason, us will begin our discovery by imagining a wall surface that has been constructed of bricks, prefer the one in the adhering to picture. Can you see exactly how the wall surface is do of countless identical bricks?

A brick wall.

Similarly, we deserve to think that most forms of matter as being consisted of of many, many little particles. These small particles are referred to as atoms.

What room atoms?

The early Greek thinkers proposed the all matter is comprised of incredibly little but discrete units (like the bricks in our wall example). Democritus (460 - 370 BC) to be the very first to speak to these devices atomos. Native this phrase came the term atom the we usage today.

Democritus very first used the termatomosmore than 2000 years ago to explain the smallest fragment that issue is made of. It took a an extremely long time (more than 2000 years!) because that the principles of Democritus to be accepted by scientists. Why do you think it take it so long? talk about this in your class.

Get learner to comment on this in class for a few minutes. You could steer the discussion with the adhering to questions:

do you think in vampires? (Fairies, zombies, the Easter Bunny, Thokoloshe, etc.) perform you think they yes, really exist? once do we know something really exists? (When we have hard evidence for its existence.) can it it is in that scientists did not believe in the existence of atoms since they can find no hard evidence for your existence? Why carry out you think scientists might not uncover evidence for the presence of atoms? might it be since atoms are so incredibly little that they can not be viewed by the nude eye?
Atoms room so small that until recently, it was difficult to watch them, also using the strongest microscope. Recently there are microscopes connected to sophisticated computer software, which do it feasible for scientists to in reality "see" atoms.

have the right to you imagine how difficult it must have actually been to to convince those at an early stage scientists the matter consists of really, really tiny particles the no-one has ever seen?

Atoms are so little that a glass that water contains more atoms 보다 there are glasses of water in the Atlantic Ocean.

How little are atom really? Well, about 5 000 000 000 000 000 000 of them would certainly fit inside the complete stop at the end of this sentence. Of course different atoms have different sizes, for this reason this is simply an approximate number. Wait... Atoms have various sizes? how does the work? In the next section, us will find out.

What room elements?

Democritus" ideas about matter were ignored and forgotten for more than 2000 years, until an brother by the name of john Dalton reintroduced them to the scientific human being in 1803. Dalton made five claims around atoms that room still largely welcomed as the truth today. 3 of this claims, or postulates together they are more commonly called, phone call us just how to understand elements. Us will acquire to the staying two postulates later. Here is what Dalton taught us around elements:

Each facet consists of indivisible, minute particles called atoms.

All atoms of a given facet are identical.

Atoms of different facets have various masses.

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This ties in v what us learnt about the facets in Gr. 7 Matter and also Materials. Let united state revise what we already know:

The regular Table of elements was initially made to stand for the patterns observed in the chemistry properties the the elements. Each facet has a fixed position on the regular Table. The elements are i ordered it in order of raising atomic number.

The aspects are arranged in order of increasing atomic number.
you can find a larger version of the regular Table top top the within cover of your book for simple reference.