Introduction to Ionic Compounds

Contributed by:

Jonathan James Fri, Jan 14, 2022 07:21 PM UTC

The highlights are:
1. Ionic vs Covalent
2. Monoatomic vs Polyatomic
3. Ionic Bond
4. Lewis Structures
5. Transition Metals

1. Ionic Compounds

2. Previous Information to
Remember!!!
 Charges of ions of representative
elements
 Which types of elements form
positive ions vs negative ions
 Polyatomic ions (on formula chart)
– Their Lewis structures
 Element symbols
 Cations and anions

3. Ionic vs. Covalent
 How do you tell
if a compound
is ionic or
covalent?
– Ionic is a metal
(cation) and a
nonmetal
(anion)
– Covalent is two
nonmetals

4. Monatomic vs Polyatomic
 Monatomic
– 1 atom
– Na+1, Al3+, S2-, Cl1-
– Anions end in “-ide”
 Polyatomic
– 2 or more atoms bonded together
– NO31-, SO42-, OH1-, NH41+
– Anions typically end in “-ate” or “-ite”

5. Ionic bond – Transfer of
Electrons
 What is the charge
of the sodium ion?
 What is the charge
on the chloride
ion?
 What is the overall
charge of the
sodium chloride
compound?

6. Ionic bond – Transfer of
Electrons
 What is the charge
of the magnesium
ion?
 What is the charge
on the oxide ion?
 What is the overall
charge of the
magnesium oxide
compound?

7. Ionic bond – Transfer of
Electrons
 What is the charge
of the magnesium
ion?
 What is the charge
on the fluoride ion?
 What is the overall Why was there 1 cation
charge of the and 1 anion in
magnesium magnesium oxide but 1
cation and 2 anions in
fluoride magnesium fluoride?
compound?

8. Binary Ionic Compounds
 Two elements – one metal, one
nonmetal
 Metal gets written first
 Nonmetal gets written second, but
change ending to –ide i t
i s as
 Examples: hy e n d
W tt i n a e
r r
– BeCl2 – Beryllium chloride w Cl 2 the
Be if o
– Al2O3 – Aluminum oxide O 3 n ?
Al 2 are xes
e fi
pr

9. Total charges of ions must
equal zero!!!
 Mg F  What if the
ions have
 How many fluorines will the same
you need? numerical
 Al charge?
O
 Ca S

10. Drop and Swap!!!
 Write the ions
 Drop the charges down (as
subscripts) and swap charges with
other atom
Write as
empirical
formula!
!!

11. Do
Page
5

12. Number Answer
1 NaBr Check your
3 MgS
5 Li3P Answers for
7 KI the Odds!!!
9 Rb3N
11 Potassium oxide
13 Aluminum chloride
15 Sodium nitride
17 Barium phosphide
19 Strontium fluoride

13. Lewis Structures
 Draw the Lewis dot structures of each
element in compound
 Transfer electrons from metal to nonmetal
 Add enough of each element (as needed)
to transfer the correct number of electrons
 Brackets around the anion; put charges
behind everything in compound

14. Polyatomic Ions
Formed when more than one atom are grouped
Charge on polyatomic ions applies to entire group of
The polyatomic ion acts as an individual ion and is
Common Polyatomic
protected with parenthesize in the formula!
NH4+ Ions
Ammonium
 Typically end in –ate or -ite
Sulfate
NO3- Nitrate
Carbonate
OH- Hydroxide
CO32- Carbonate
SO42- Sulfate
PO43- Phosphate
NO -
Nitrite

15. Lewis Structures
of Polyatomics
 How many
Oxygen does
nitrate have?
 Its charge?
 How many
Oxygen does
phosphate have?
 Its charge?

16. Dropping and Swapping
with Polyatomics
 You have to keep the
K+1 PO43-
same # of O!!!
 Drop and swap the K3PO4
charge!!!
Ba2+ NO3-
 What’s the  Ba(NO3)2
difference between
MgOH2 and Mg(OH)2?

17. Practice
 Magnesium chlorate: Mg(ClO 3)2
_____________
 Ammonium chloride: NH
4Cl
_____________
 MgCO3: _______________________
Magnesium carbonate
 K2SO3: ________________________
Potassium sulfite
 Aluminum dichromate:Al_____________
2(Cr2O7)3
 Calcium hydroxide: ________________
Ca(OH)2
 NaNO3: _________________________
Sodium nitrate

18. Do
Page
6

19. 1
Answer
Na2CrO4
Check your
3 Mg(NO3)2 Answers!!!
5 Li3PO4
7 CsClO3
9 Ba(C2H3O2)2
11 Potassium acetate
13 Aluminum chlorate
Strontium
15
bicarbonate
17 Lithium carbonate
19 Cesium chromate

20. Transition Metals and
Roman Numerals
 Transition metals (and Sn, Pb, Bi) do not have set
charges
 Can form variable ions (ex. Fe2+ or Fe3+)
 Roman Numerals are used indicate charge of
transition metals
– Copper (II) = Copper +2
– Iron (III) = Iron +3
 Some transition metals do have set charges
– Zn2+, Cd2+, Ag1+

21. Writing Names and
Formulas
 UseRoman numeral in name to write
formula
– Example: Cobalt (III) chloride – CoCl3
– Example: Tin (IV) sulfate– Sn(SO4)2
 When
going name to formula, include
Roman numeral in name (except for Zn, Cd,
Ag)
– Example: Ni(NO3)2 – Nickel (II) nitrate
– Example: Au2O – Gold (I) oxide

22. Practice
 ZnCl2: ________________________
Zinc chloride
FePO4
 Iron (III) phosphate: ________________
 Chromium (II) bromide: CrBr______________
2
Lead (IV) oxide
 PbO2: ___________________________
 Silver sulfate: Ag
2SO4
____________________
Copper (I) nitrate
 CuNO3: _________________________
Nickel (III) sulfite
 Ni2(SO3)3: ________________________

23. Pay careful
Do attention on
when to use
Page
Roman
numerals
and when
7 not to also
when you
have a
odds!! polyatomic
ion involved
vs. a

24. 1
Answer
CuSO4
Check your
3 Cr(CN)3 Answers!!!
5 AgBr
7 Fe(C2H3O2)3
9 Iron (II) chloride
11 Cobalt (III) carbonate
13 Zinc cyanide
Chromium (III)
15
hydroxide
17 Au3N
19 Mn(NO2)2
21 Tin (II) hydroxide
23 Zn3P2

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