Everything Science Grade 10

4.6 CHAPTER 4. THE ATOM

Element No. of energy

levels

No. of electrons Electron configuration

(standard notation)

Mg

K

S

Ne

N

Ca2+

Cl−

3. Rank the elements used above in order ofincreasing reactivity. Give rea-

sons for the order you give.

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(1.-3.) 0018

Earlier in this chapter, we talked about different “models” of the atom. In science, one of
the uses of models is that they can help us to understand the structure of something that we
can’t see. In the case of the atom, models help us to build a picture in our heads of what
the atom looks like.

Group Discussion:Building a model of an atom

In groups of 3-4, you are going to

build a model of an atom. Each group

will get a different element to repre-

sent. Before you start, think about

these questions:

• What information do I have
  about the structure of the atom?
  (e.g. what parts make it up? how
  big is it?)


• What materials can I use to rep-
  resent these parts of the atom as
  accurately as I can?


• How will I put all these different

parts together in my model?

As a group, share your ideas and then

plan how you will build your model.

Once you have built your model, dis-

cuss the following questions:

• Does our model give a good idea
  of what the atom actually looks
  like?


• In what ways is our modelinac-
  curate? For example, we know
  that electronsmove around the
  atom’s nucleus, but in your
  model, it might not have been

90 Chemistry: Matter and Materials