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Structure
and bonding
Francine
Taylor-Campbell, Contributor
Now
let us examine some questions.
Circle
the correct answer to the following
questions.
1.
Which solid does not contain covalent
bonds?
A.
Copper
B.
Diamond
C.
Graphite
D.
Ice
2.
The elements X and Y form the compound
X2Y. What is the correct electron
arrangement of the atoms X and Y?
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Atom
X
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Atom
Y
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A
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2
: 7
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2
|
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B
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2
: 2
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2
: 7
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C
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2
: 2
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2
: 6
|
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D
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2
: 1
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2
: 6
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3.
In which set do the three particles
each have the same total number of
electrons?
A.
Cl- Br- I-
B.
F- Ne Na+
C.
K+ Ca2+ Br-
D.
Li+ Na+ K+
4.
What is the formula of iron (III)
nitrate?
A.
Fe (NO3)3
B.
Fe2 (NO3)3
C.
Fe2NO3
D.
Fe3(NO3)2
5.
Elements X and Y react to form an
ionic compound of formula XY. What
could be the proton (atomic) numbers
of X and Y?
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X |
Y |
| A
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3 |
8 |
| B |
6 |
8 |
| C
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8 |
16 |
| D |
12 |
16 |
ANSWERS
AND COMMENTS
1.
Answer - A
Covalent
bonds are formed between non-metals.
Diamond and graphite are made up of
carbon, which is a non-metal, while
ice (frozen H2O) consists
of bonds between hydrogen and oxygen
which are also non-metals. This leaves
copper which exhibits metallic bonding.
2.
Answer - D
From
the formula, Y would form the ion
Y2- and 2X+
ions would combine to produce X2Y.
This means that Y is in Group 6 (VI)
needing 2 electrons to be stable and
X is in Group I since it has lost
one electron to be stable. Thus the
electron arrangement for X is 2:1
and for Y is 2:6.
3.
Answer - B
Fluorine
gains an electron to have the electron
arrangement 2:8, the neon atom is
2:8 and sodium loses an electron to
have a 2:8 arrangement. This totals
10 electrons for all three particles.
4.
Answer - A
Iron
(III) has a charge of +3 and the nitrate
ion (NO3)- has a charge of -1. These
ions must combine in a way so that
their charges cancel out to zero.
Thus it will take 3 nitrate ions (3
x -1) = -3 to cancel out the +3 charge
on one iron. -3 + 3 = 0.
5.
Answer - D
X
has the arrangement 2:8:2 and Y has
the arrangement 2:8:6. Thus as X loses
2 electrons to be stable, they are
gained by Y which needs 2 to be stable.
It requires one X to bond with one
Y. The formula is XY.
Please
note: It is important to review the
notes on this topic so that you can
answer structured and essay-type questions
as well.
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Nickolae
Fletcher (right), customer resource
officer Jamaica Wellness Cluster,
shows off her product to students
from Stony Hill Heart Academy
at the Jamaica Small Business
Development Centre's second
annual small business expo.
The expo was held at the Hilton
Kingston hotel in St Andrew
on Wednesday, May 6.
- Norman Grindley/Chief Photographer
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Francine
Taylor-Campbell is an independent
contributor.
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