Download ionic and covalent bonding - Atomic Theory and Periodic Table

MODULE 1
WORKSHEET
9
IONIC AND COVALENT BONDING
Syllabus reference 8.2.3
1
Complete the following to check your understanding.
a
element
Every pure substance is either an _______________
or a compound. A compound is either
ionic
molecular or _______________
in nature.
b
ions
Ionic compounds are composed of oppositely charged _______________.
Although ionic
compounds are made up of charged particles, the overall compound is electrically
neutral
negative
_______________.
This means that the total number of positive and _______________
charges
equal
are _______________.
c
cations
loses
The positively charged ions, called _______________,
are formed when an atom _______________
negative
electrons. These positive ions are attracted to the _______________
ions, called anions, which are
gains
formed when an atom _______________
electrons. The result of this attraction is the formation
ionic
attractive
of an _______________
compound held together by _______________
forces. The charges on the
Periodic
monatomic ions can be determined by the position of the element in the _______________
Table.
d
ratio
The formula of an ionic compound is actually the _______________
in which the ions are
present. This can be easily determined because the overall charge on an ionic compound must
neutral
be _______________.
As this formula gives a ratio rather than actual numbers of ions, it is
empirical
called an _______________
formula.
e
atoms
Molecules are composed of two or more _______________.
These atoms, are held together
sharing
covalent
by _______________
electrons between pairs of atoms. This sharing is called _______________
bonding. Covalent molecular substances may be elements, when the atoms are the
same
compounds
_______________
or _______________
when the atoms are different.
Copyright © 2008 McGraw-Hill Australia
CONQUERINGCHEMISTRY PRELIM
MODULE 1 WS 9
gain
Covalent bonding occurs when both atoms need to _______________
electrons to attain
f
shared
noble gas configuration. When one pair of electrons is _______________
the result is a single
covalent bond.
g
right
Elements in the centre and to the _______________
of the Periodic Table tend to form
covalent bonds. The number of covalent bonds an atom forms is the number of
electrons
_______________
that atom needs to gain to attain noble gas configuration.
2
State the number of electrons lost or gained in forming each of the following ions and state
whether they are anions or cations.
SYMBOL
NUMBER OF ELECTRONS
LOST OR GAINED
Mg2+
2 lost
cation
Ag+
1 lost
cation
Ca2+
2 lost
cation
Br–
1 gained
anion
O2–
2 gained
anion
3
Write a formula for each of the following compounds.
MgCl2
a Magnesium chloride
CaO
b Calcium oxide
K2S
c Potassium sulfide
AlF3
d Aluminium fluoride
4
a
b
ANION OR CATION
What is the ionic charge of element X in each of the following compounds?
i
XF
1
ii
XO
2
iii
X2S
1
iv
X2S3
3
What is the ionic charge of Y in each of the following compounds?
i
MgY2
1
ii
Na2Y
2
iii
Li3Y
3
iv
Al2Y3
2
Copyright © 2008 McGraw-Hill Australia
CONQUERINGCHEMISTRY PRELIM
MODULE 1 WS 9
5
6
Write the formula for each of the following compounds formed between:
a
boron and chlorine
BCl3
b
phosphorus and iodine
PI3
c
hydrogen and bromine
HBr
d
nitrogen and oxygen
N2O3 or NO2
Draw Lewis electron dot structures for the following molecules.
a
e
H2
����
b
���
f
HCl
g
NH3
���������
�
d
Mg2
Mg
� ����
c
O2
F
���
K
K
7
8
Write ionic equations showing the formation of ions from the following neutral elements.
a
Potassium
K → K  e
b
Strontium
Sr → Sr2  2e
c
Aluminium
Al → Al3  3e
d
Iodine
I  e → I
e
Sulphur
S  2e → S2
f
Nitrogen
N  3e → N3
Classify the following statements as true (T) or false (F). For those statements that are false, alter
them to be correct.
a
A molecule must contain two different elements joined together.
FALSE
b
A molecule must contain two OR MORE ATOMS joined together.
Elements tend to undergo chemical reactions to form compounds in order for their
atoms to obtain noble gas configuration.
TRUE
c
The formula for hydrogen gas is H.
FALSE
d
The noble gases exist as diatomic molecules.
FALSE
e
The formula for hydrogen gas is H2.
The noble gases exist as MONOATOMIC molecules.
Elements in the same group will always form the same number of covalent bonds.
TRUE
Copyright © 2008 McGraw-Hill Australia
CONQUERINGCHEMISTRY PRELIM
MODULE 1 WS 9