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Metals
& non-metals
Francine
Taylor-Campbell, Contributor
YOU
SHOULD BE ABLE TO:
- List
the physical and chemical properties
of non-metals
- Investigate
the reactions of non-metals with
oxygen and metals
POINTS
TO NOTE
- Non-metals
are generally found between groups
5 and 7 of the periodic table
- A
non-metal is an element which forms
ions by gaining electrons and is
said to be electronegative
-
Non-metals are oxidizing agents
as they react by gaining electrons
N + n e ===== Nn-
- Non-metals
react with air or oxygen to form
acidic oxides which can dissolve
in water to form acids
- Non-metals
do not react with dilute acids,
water or steam
- They
form covalent compounds with other
non-metals and ionic compounds with
metals.
The
reactivity of a non-metal is based
upon how readily it gains electrons
or its affinity for electrons. For
example, in Group 7 of the periodic
table, the halogens, the most reactive
element, is at the top of the group.
This is because its outer shell is
closer to the nucleus than the element
at the bottom of the group, hence
its attracting power for electrons
is greater. So fluorine is more reactive
and electronegative than chlorine,
which is more reactive than bromine.
Based
on your knowledge of the reactions
of both metals and non-metals, answer
the questions given below.
Q1.
Use the list of elements to answer
the questions that follow.
| Bromine |
Carbon
|
Chromium |
Helium |
| Magnesium |
Phosphorous
|
Sodium |
Sulphur |
Choose
one element which
a.
Forms a basic oxide
b.
Has a high density and forms coloured
compounds
c.
Is composed of diatomic molecules
d.
Is a liquid at room temperature and
pressure
e.
Exists as allotropes
ANSWERS
a.
Magnesium, chromium and sodium are
all metals, hence they react with
oxygen to form basic oxides
b.
Chromium, as it is a transition metal.
Metals have high density and coloured
compounds are formed by transition
metals.
c.
Bromine - the formula is Br2, ie 2
atoms of bromine
d.
Bromine is a liquid at room temperature
and pressure
e.
Carbon, phosphorous and sulphur exist
as allotropes.
Remember,
allotropes are different forms of
an element in the same state having
different physical properties but
the same chemical properties. The
allotropes of carbon are diamond,
graphite and buckminsterfullerene
(C60). Allotropes of phosphorous are
white and red phosphorous, and monoclinic
and rhombic sulphur are allotropes
of sulphur.
Francine
Taylor-Campbell teaches at Jamaica
College. Send questions and comments
to kerry-ann.hepburn@gleanerjm.com
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