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Elements
Earlier in this module, you considered the diversity of your surroundings in terms of
matter. Although matter can take many different forms, all matter can be broken down
into a relatively small number of basic building blocks called elements. An
element
is a pure substance that cannot be separated into simpler substances by physical or
chemical means. On Earth, over 90 elements occur naturally. Copper, oxygen, and gold
are examples of naturally-occurring elements. Elements are found in different physical
states in normal conditions, as shown in
Figure 13
. There are also several elements that
do not exist naturally but have been developed by scientists.
Each element has a unique chemical name and chemical symbol. The chemical symbol
consists of one, two, or three letters; the first letter is always capitalized, and the
remaining letter(s) are always lowercase. The names and symbols of the elements are
universally accepted by scientists world-wide in order to make the communication of
chemical information possible.
Copper pot—solid
Helium balloon—gas
Mercury switch—liquid
Figure 13
In normal conditions, elements exist in different states.
Disciplinary Core Ideas
Crosscutting Concepts
Science & Engineering Practices
3D THINKING
C
C
C
S
E
P
D
C
I
COLLECT EVIDENCE
Use your Science Journal to
record the evidence you collect as
you complete the readings and
activities in this lesson.
INVESTIGATE
GO ONLINE
to find these activities and more resources.
ChemLAB:
Identify the Products of a Chemical Reaction
Obtain, evaluate, and communicate information
to determine the
cause and effect
of a
chemical reaction.
Inquiry into Chemistry:
Is it gold or fool’s gold?
Construct an explanation
for the importance of examining
the structure
of an unknown material.
FOCUS QUESTION
What are elements and compounds?
LESSON 3
ELEMENTS AND COMPOUNDS
60
Module 2 • Matter—Properties and Changes
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