Download Multivalent Ionic Compounds

BCLN SCIENCE 10 - Rev. Mar /2016
Unit 4 ~ Learning Guide Name:
INSTRUCTIONS
Complete the following practice questions as you work through the related lessons.
You are required to have this package completed BEFORE you write your unit test.
Do your best and ask questions about anything that you don't understand BEFORE you
write the unit test.
Please print out the Formula Sheet found at the start of the course. You will
need this to do assignments and tests!
4.1 NOTES: Atomic Theory and Bonding
Atoms join together to form

.

is a single molecule of a substance
The element, oxygen, is O. The oxygen molecules we breath are O 2
Compounds are also pure substances, but are

Oxygen and hydrogen are atoms/elements; H2O is a compound
o
A chemical change occurs when
to form new compounds.
Atomic Theory
Atoms are made up of smaller particles known as
.
Name Symbol Charge
Location
Relative Mass
Proton
p
1+
nucleus
1836
Neutron
n
0
nucleus
1836
1–
area
surrounding
the nucleus
1
Electron
e
Page 1 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
The nucleus is at the





of an atom.
The nucleus is composed of
Electrons exist in the space surrounding the nucleus called shells.
# of protons =
Nuclear charge =
Atomic number =
Organization of the Periodic Table
The periodic table organizes all known elements.

Elements are listed in order by

Metals are on the
group 3 to group 12), non-metals are on
form a “staircase” in the middle.
Page 2 of 35
(the transition metals range from
, and the metalloids


BCLN SCIENCE 10 - Rev. Mar /2016
Rows of elements (across) are called
.
o All elements in a period have their electrons in the same general area
around their nucleus
Columns of elements are called
o All elements in a family have similar properties, and bond with other
elements in similar ways
o
o
o
o
Group 1 =
Group 2 =
Group 17 =
Group 18 =
Ion Formation
Atoms




to form bonds.
The atoms become electrically charged particles called ions.
(= cations)
o Some metals (multivalent) lose electrons in different ways
o ie. Iron, Fe, loses either 2 (Fe2+) or 3 (Fe3+) electrons
( = anions)
Atoms do this in an attempt to have the same number of valence electrons
(electrons furthest from the nucleus) as the
.
Patterns in the Periodic Table
Electrons appear in
a maximum of
in the 3rd shell.
in a very predictable manner. There is
electrons in the first shell,
in the 2nd shell, and
Page 3 of 35
BCLN SCIENCE 10 - Rev. Mar /2016



The period # = # of shells in the atom.
Except for the transition elements, the last digit of the group # = # of electrons in
the valence shell
The
elements have
, and are very stable.
Bohr Diagrams
Bohr diagrams show



Each shell holds a maximum number of electrons
Electrons in the outermost shell are called
Think of the shells as being 3D like spheres, not 2D like circles
What element is this?



It has 2 + 8 + 8 = 18 electrons, and therefore 18 protons. # of
electrons = # of protons (In a neutral atom)
It has 3 electron shells, so it is in period 3
It has 8 electrons in the outer (valence) shell
Page 4 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
ARGON!!!
Forming Compounds
When two atoms get close together, their
.




If the valence electrons can combine to form a low-energy bond, a compound is
formed.
Each atom in the compound attempts to have the stable number of valence
electrons as the nearest noble gas. (This is stable)
Metals may lose electrons and non-metals gain electrons, (
OR
Atoms may share electrons (
)
Ionic bonds form when
cations to anion. Metal + non-metal = ionic bond

from
Cations want to donate an electron(+) and anions want to accept more electrons(-)
Covalent bonds form when
metals. Non-metal + non-metal = covalent bond

between two non-
Electrons stay with their atom, but overlap with outer shells
Ionic bonds



)
Formed between cations (+ ions) and anions (- ions)
Generally, this is a
For example, lithium and oxygen form an ionic bond in the compound Li 2O
Page 5 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
Covalent Bonds


Formed between
Electrons are
electron in the examples below)
between atoms (as shown by the red
Lewis Diagrams
Bohr diagrams are very illustrative, but Lewis diagrams are very efficient when
showing atoms and their bonding capabilities.



Dots representing electrons are placed around the element symbols at the points of
the compass (north, east, south, and west)
Electron dots are placed singly, until the fifth electron is reached, then they are
paired.
Page 6 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
Lewis diagrams make drawing ions, and ionic bonds much less work than Bohr
diagrams.



For positive ions, one electron dot is removed from the valence shell for each
positive charge of the ion.
For negative ions, one electron dot is added to each valence shell for each
negative charge of the ion.
Square brackets are placed around each ion to indicate transfer of electrons
Lewis diagrams of covalent bonds are also very easy.



Like Bohr diagrams, valence electrons are drawn to show
.
All atoms wish to have a full valence shell
The shared pairs of electrons are usually drawn as a straight line
Diatomic molecules, like O2, are
also easy to draw in Lewis form
Page 7 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
4.1 PRACTICE: Atomic Theory and Bonding
1. Complete the wordsearch, 4.1 quiz and 4.1 Check Your Understanding.
2. Why is oxygen considered an element but water is a compound?
3. Fill in the chart below.
Name
Symbol Charge
Location
Relative Mass
Proton
Neutron
Electron
4. If the number of electrons (-) and the number of protons (+) in an atom are equal, what
must the overall charge in every atom be?
5. What "shape" separates metals from non-metals on the periodic table?
6. What is the name for columns and rows on the periodic table.
7. What are the names for positive and negative ions?
Page 8 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
8. What is the maximum number of electrons allowed in each of the first 3 shells? Memorize
this!
9. Draw a Bohr diagram for the following atoms (remember atoms are always
neutral).
Write the number of protons (p) and neutrons (n) on the inside of each atom.
a. Boron
p:
n:
b. Aluminum
p:
n:
Page 9 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
c. Nitrogen
p:
n:
d. Phosphorus
p:
n:
Page 10 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
10. Which type of atom can form a covalent bond and which type can only form an ionic
bond?
11. Draw a Bohr diagram for the following ions
a. Aluminum
p:
n:
d. Phosphorus
p:
n:
Page 11 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
12. Draw Lewis Diagrams for the atoms and ions of the first 18 elements in the
Periodic Table. If the element does not form an ion simply state “no ion”. The
first two are done for you as an example. Hint: Ions are usually formed by losing
all electrons in the Lewis diagram or gaining enough to create a full Lewis
diagram. Ions are shown in brackets with the charge on the outside.
Atomic
Number of
Element
Group
Number
Lewis Diagram of Atom
1
1
H
[H] +
Cat
2
18
He
No ion
N/A
3
4
5
6
7
8
9
Page 12 of 35
Lewis Diagram of Ion
Cation or
Anion?
BCLN SCIENCE 10 - Rev. Mar /2016
Atomic
Number
of
Element
Group
Number
Lewis Diagram of Atom
Lewis Diagram of Ion
Cation or
Anion?
10
11
12
13
14
15
16
17
18
13. Draw Lewis structures for an N2 molecule and the ionic compound Na2O.
Page 13 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
4.2 NOTES: Names and Formulas of Compounds
Ionic vs Covalent
Ionic compounds are made up of



All of the positives and negatives organize nicely.
o Negative-positive
o Negative-negative and positive-positive
.
Ionic compounds form from the inside-out as solid crystals
Ionic compounds are like a solid stack of bricks!
o A salt shaker contains thousands of small pieces of
NaCl salt
Covalent molecules



.
There is generally no order to the formation of covalent molecules
These molecules clump together as solids, liquids or gases
Covalent molecules are like a play-pit full of plastic balls
o Each plastic ball = 1 covalent molecule of H2O
o Pit full of balls = swimming pool full of water
Ionic Compounds
Writing formulas for ionic compounds


In an ionic compound, the positive charges
The ratio of positive:negative charges gives the proper formula
o The ratio is always written in reduced form
the negatives
For example: What is the formula for magnesium phosphide?
Step 1 : Find the symbol and charge for each element.
Step 2: (option A) Cross down the charge from each element to the other or
(option B) find the lowest common multiple of 2 and 3 is 6
Option A –
Page 14 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
Option B - 3Mg2+ ions and 2P3– ions
For Example :Try the formula for calcium oxide
Step 1: calcium is Ca2+ oxygen is O2–
Step 2:
option A option B - 1Ca2+ ion and 1 O2– ions
Ca2O2, which is simplified and written as
Naming Ionic Compounds
Ionic compounds are composed of cations and anions.

The name of an ionic compound is formed by writing
as seen on the periodic table and then adding the
name of the anion and changing its ending to

For example, an ionic compound forms between magnesium and oxygen
o The cation is the first part of the name, magnesium
o The anion forms part of the ending of the name, ox ygen
o Add -ide to the end of the name to form magnesium oxide .
Ionic formulas are based on the ions of the atoms involved


Remember the naming principles above
For example, what is the name of Ca3N2 ?
o Ca, the cation, is calcium
o N, the anion, is nitrogen
o Drop the end of the anion and add -ide
o
Page 15 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
Multivalent Ionic Compounds
Some transitional metals are
, meaning they
have more than one ion form.
 On the periodic table, the most common form of the ion is listed on top
 In the name of the compound
are used
following the cation to indicate which ion was used.
For example, what is the formula for
sulphide?
This is
as indicated by the (III) in
the name. Once that is determined the rest is the same as naming
ionic compounds.
Step 1: Mn3+ and S2Step 2:
option A option B - lowest common multiple, 2Mn3+ ions and 3S2- ions
For Example: Try the name for TiF4
Step 1: decide if we use Ti3+or Ti4+ and F-, note that the 4 in the compound (TiF4)
crossed down from the Ti so we must have used Ti4+.
Step 2: name the multivalent metal as is on the periodic table, Titanium, add the
roman numeral (IV) to indicate the charge used and then add the nonmetal, changing the ending to -ide, flouride.
Ionic Compound- Polyatomic Ions
Some ions, called polyatomic ions, are made up of
(ironically, joined with covalent bonds).



The whole group has a + or – charge, not individual atoms.
Polyatomics can be identified easily because the compound will have
in it. eg. NaCO3
(3 capital letters so one is polyatomic ion)
What is the formula of sodium sulphate?
Page 16 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
Steps remain the same as if we were creating an ionic compound but this time we see
the polyatomic ion as one element instead of individuals.
Step 1: find the symbols of the elements and their charges, polyatomics will be
found on
not the periodic table. Na+ and
SO42Step 2:
the charges, any charge crossed down to
a polyatomic must be put outside brackets as it applies to the entire
polyatomic ion.

The result would be Na2(SO4)1, but since we do not need to write the 1 it
becomes
What is the name of the compound KClO?
Step1: Name the metal off the periodic table, K =
Step 2: Find the polyatomic on the polyatomic list and write name as it is found,
ClO = hypochlorite
Covalent Compounds
Covalent compounds, also called
chemical formula to reveal the components of the molecule.



Covalent compounds are made up of two or more
Names may reveal the components, but often do not
Subscripts mean something different in covalent compounds
o Ionic compounds subscripts show smallest
between the ions in the compound
o Covalent molecules have subscripts that show
of atoms in the molecule
Page 17 of 35
, rely on the
.
BCLN SCIENCE 10 - Rev. Mar /2016
What is the chemical formula for the molecule ethanol?
C2H6O, a name that must be memorized or looked up when needed

What is the name of the molecule C12H22O11?
, aka table sugar
Binary covalent compounds (
of prefixes.

) use a system
Covalent compounds may have many or few atoms sharing electrons
o CH4 = methane and C25H52 =
o
Prefixes are often
o
o
to
indicate the number of atoms in the molecule.
CO = carbon monoxide, CO2 = carbon dioxide
Write the
(furthest left) first
to end of the second
atom’s name
o
What is the chemical formula for the molecule trinitrogen
tetrachloride?
Step 1:
for each element, charge is not important in covalent
bonding. Nitrogen = N, Chloride = Cl
Step 2: Determine
is represented by the prefixes, tri = 3 and tetra = 4
N3Cl4
What is the name of the molecule Si3P6?
Step 1: Determine the name for each element from the periodic table.
Step 2: Find the prefix from the number given to each.
Step3: Join the prefix to each element remembering to change the ending of the
second element to -ide.
Page 18 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
Determining Ionic Vs Covalent
To determine whether a compound is
:
1. Examine the formula


or the ammonium ion
Covalent compounds
2. If the compound is covalent…


system of naming if the compound is
binary and does not start with hydrogen
If there are
, or it starts with H,
there is probably a different, simpler name for the covalent molecule
3. If the compound is ionic



Check the metal to see if it is
(add a roman
numeral if it is multivalent). Naming starts with the name of the metal atom.
If it ends with a single non-metal,
If it ends in
, look up the name/formula in
the polyatomic ion chart.
Page 19 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
4.2 PRACTICE: Names and Formulas of Compounds
1. Complete Names and Formulas of Compounds challenge, 4.2 crossword, 4.2
Quiz, and 4.2 Check Your Understanding.
2. Determine the formula of each of the following monovalent ionic compounds.
Use your periodic table to look up the charge on each ion. If you use the
crossover method be careful on the third and fourth questions as you need to
reduce your numbers!
Compound
Metal Ion
Non-Metal
Ion
lithium and selenium
calcium and arsenic
hafnium and sulfur
aluminum and nitrogen
3. Name the following monovalent ionic compounds:
Formula
Name
LiF
CaCl2
Sc2S3
Rb2O
Page 20 of 35
Formula
BCLN SCIENCE 10 - Rev. Mar /2016
4. Determine the formula of each of the following polyatomic compounds. There is a
page in your data booklet which has the names and formulas of polyatomic
ions. Be careful to use brackets if and ONLY if they are needed! They are
needed ONLY if you have more than one of a polyatomic ion in your compound.
Compound
Positive Ion
Negative Ion
Formula
sodium and
bicarbonate
calcium and sulfate
barium and phosphite
ammonium and
sulfur
ammonium and
phosphate
5. The names of compounds made from certain metals require roman numerals in
them. What name do we give these metals?
6. When looking at your periodic table how will you recognize that a metal will
require a roman numeral?
Page 21 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
7. Determine the formula of each of the following multivalent ionic compounds. Be careful
to always start your formula with a metal NOT a non-metal!
Compound
Metal Ion
Non-Metal
Ion
Formula
chromium (III) and
phosphorus
nickel (II) and chlorine
iodine and mercury (I)
lead (IV) and oxygen
8. Name the following multivalent ionic compounds. Use the work space provided to show
how you determined the correct roman numeral
Formula
Work
Name
MnO
MnO2
Fe2O3
Hg2S
Page 22 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
9. When looking at formulas, what is the easy way to identify a polyatomic compound?
10. The names of all simple ionic compounds end in IDE. What are the two most
common three letter endings for polyatomic compounds?
11. Name the following polyatomic compounds. IF and only if the metal is multivalent, be
sure to include a roman numeral in the name and use the space provided to show
how you determined the correct roman numeral.
Formula
Work
Name
NaOH
Mg(CN)2
MnSO4
Mn(SO4)2
(NH4)3PO3
Pd(Cr2O7)2
Page 23 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
12. To do names and formulas for ionic compounds correctly you must balance your
charges. This may require a little math. Do you ever need to do any math when
naming or providing formulas for covalent compounds?
13. How can you recognize that you have a covalent compound instead of an ionic
compound?
14. Determine the formula of each of the following covalent compounds.
Name
Formula
trisilicon pentoxide
dinitrogen tetrafluoride
dihydrogen monoxide
carbon monoxide
15. Name the following covalent compounds. Be careful with MONO! You should never
start a name with MONO but you can have MONO in the middle of the name.
Formula
Name
P3Cl7
BO4
Cl3I6
Si3I
Page 24 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
16. For each of the following determine if the compound is ionic, has polyatomic ions or is
covalent. Simply put an I, P or C in the box! Note that all compounds with polyatomic
ions contain both covalent and ionic bonds.
Ionic (I),
Polyatomic (P)
or
Covalent
(C)
Name or
Formula
MgCl2
CO2
NH4Cl
diphosphorus pentaoxide
magnesium bicarbonate
ammonium
selenide
B 2 I2
AlF3
Fe2S3
dihydrogen
dioxide
ruthenium (III) nitrate
Ca(NO2)2
sulfur
monoxide
Page 25 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
4.3 NOTES: Balancing Chemical Equations
Chemical reactions result in


.
Chemical changes occur when new substances are created.
The original substance(s), called
substance(s) called
.
, change into new
Chemical reactions can be written in different ways.

A
o

A
o
:
Nitrogen monoxide + oxygen --> nitrogen
dioxide
:
2NO(g) + O2(g) --> 2NO2(g)
Coefficients (big numbers in front of compounds)
- indicate the ratio of compounds in the reaction
- here, there is
NO2 than there is O2
as much NO and
State of matter
- Letters indicate the state of each compound
(aq) =
(s) =
(l) =
(g) =
Conservation of Mass
Chemical change means

are created.
BUT no new matter is created or destroyed; atoms are just

.
=
Page 26 of 35
BCLN SCIENCE 10 - Rev. Mar /2016

John Dalton, 200 years ago, realized that atoms simply rearrange themselves
during chemical reactions.

=
The Law of Conservation of Mass

In chemical reactions, atoms are

Developed by Antoine Lavoisier and his wife Marie-Anne in the 1700s

=
Writing Chemical Equations
The simplest form of chemical equation is a



Not much information other than the elements/compounds involved
Potassium metal + oxygen gas --> potassium oxide
reactants appear on the left of the arrow and products appear on the right
A skeleton equation shows the formulas of the elements/compounds


K(s) + O2 (g)--> K2O(s)
A balanced chemical equation



Balancing ensures that the number of each atom is the same on both sides of
the reaction arrow
Always use the smallest whole number ratio
4K(s) + O2 (g)
2K2O(s)
Balancing Chemical Equations
Because of the Law of Conservation of Mass, we can count atoms and use math
to balance the number of atoms in chemical equations.
Page 27 of 35

BCLN SCIENCE 10 - Rev. Mar /2016
Word equation: Methane + oxygen
water + carbon dioxide
o Skeleton equation: CH4(g) + O2 (g) --> H2O(l) + CO2(g)
o To balance the compounds, take note of how many atoms of each
element occur on each side of the reaction arrow:
1 Carbon, 4 Hydrogen, 2 Oxygen --> 1 Carbon, 2 Hydrogen, 3 Oxygen

1 Carbon, 4 Hydrogen
Oxygen --> 1 Carbon,
Hydrogen,
+2 Oxygen

Balanced equation: CH4(g) + 2O2 (g) --> 2H2O(l) + CO2(g)
Balance chemical equations by following these steps:







Trial and error will work, but can be very inefficient
Balance
, elements last
Balance one compound at a time
Only add coefficients; NEVER change subscripts!
If
appear in more than one place, attempt to balance
them
Polyatomic ions (such as SO42–) can often be
Always double-check after you think you are finished!
Balance the following:
Fe + Br2 --> FeBr3
Sn(NO2)4 + K3PO4 --> KNO2 + Sn3(PO4)4
C2H6 + O2 --> CO2 + H2O
Page 28 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
Writing Word Equations
Word equations require careful examination to be written correctly.

The chemical symbol is used for most elements but not in a compound
o Be careful of diatomic and polyatomic elements such as O 2, P4 and S8
o The “special seven” are all diatomic elements


Several common covalent molecules containing hydrogen have common names
that do not help in writing chemical formulas
o For example, methane =
, glucose =
,
Ethane =
, Ammonia =
The pink shaded area in the picture below shows the diatomic atoms.
Page 29 of 35
BCLN SCIENCE 10 - Rev. Mar /2016
4.3 PRACTICE: Balancing Chemical Equations
1. Complete 4.3 wordsearch, 4.3 practice quiz, and 4.3 Check Your
Understanding.
2. In a chemical reaction, what do we call the original substances?
3. In a chemical reaction, what do we call newly made substances?
4. What are the three common states of matter?
5. If the mass of all the reactants in a chemical reaction is 100g, what will the
mass of all the products be?
6. Please balance the following reactions. Use the table to show your work.
Mg +
HCl
Reactants
Mg +
N2
Reactants
MgCl2 +
Products
Mg3N2
Products
Page 30 of 35
H2
BCLN SCIENCE 10 - Rev. Mar /2016
Ba +
HBr
Reactants
BiCl3 +
KI
Reactants
H2
Products
H2S
Reactants
Br2 +
BaBr2 +
Bi2S3 +
Products
I2 +
KBr
Products
Page 31 of 35
HCl
BCLN SCIENCE 10 - Rev. Mar /2016
Fe +
O2
Fe3O4
Reactants
CaO +
C
Reactants
Bi2O3 +
CaC2 +
I2
Reactants
CO2
Products
H2
Reactants
P4 +
Products
Bi +
Products
PI3
Products
Page 32 of 35
H2O
BCLN SCIENCE 10 - Rev. August/2014
Sn +
NaOH
Reactants
H2
Products
C6H12O6 +
O2
Reactants
C8H18 +
Na2SnO2 +
CO2 +
H2O
Products
_O2
Reactants
CO2 +
H2O
Products
7. What are the seven diatomic molecules? It is strongly recommended you memorize
these!
BCLN SCIENCE 10 - Rev. August/2014
Unit 4 Learning Guide Answers
**Please note that some answers for this section are directly from the notes. In
such cases the page number of the webpage notes will be given.
Atomic Theory and Bonding
1) Page 1, 2) Page 2, 3) Neutral or Zero, 4) Page 3, 5) Page 3, 6) Page 4, 7) 2, 8, 8,
8)
9) Covalent – two non-metals, Ionic – Metal and a non-metal.
10)
11) Group # - 1, 18, 1, 18, 2, 13, 14, 15, 16, 17, 18, 1, 2, 13, 14, 15, 16, 17, 18
Lewis Dot Diagrams:
Lewis Dot Ions: [H]+, No ion, [Li]+, [Be]+2, No Ion, No Ion, N full shell -3 charge, O full
shell -2 charge, F full shell -1 charge, No ion, [Na]+, [Mg]+2, Al full shell +3 charge, No
Ion, P full shell 3, S full shell -2, Cl full shell -1 charge, No ion.
Ion type: Cat, N/A, Cat, Cat, N/A, N/A, An, An, An, N/A, Cat, Cat, An, An, An, An, An, N/A
12)
BCLN SCIENCE 10 - Rev. August/2014
Names and Formulas of Compounds:
2) Li2Se, Ca3As2, HfS2, AlN, 3) Lithium fluoride, Calcium chloride, Scantium sulphide,
Rubidium oxide, 4) NaHCO3, CaSO4, Ba3(PO3)2, (NH4)2S, (NH4)3PO4, 5) Multivalent
compounds,
6 ) if it has more than one ion charge, 7)CrP, NiCl2, HgI, PbO2, 8) Manganese(II) oxide,
Manganese(IV) oxide, Iron(III) oxide, Mercury(II) sulfide, 9) the presence of brackets or
the presence of more than 2 capital letters. 10) “ate” and “ite” 11) Sodium hydroxide,
Magnesium cyanide, Manganese(IV) sulphate, Manganese(IV) sulphate, Ammonium
phosphite, Palladium(IV) dichromate, 12) No, 13) It’s made of two non-metals 14)
Si3O5, N2F4, H2O, CO,
15) triphosphorus heptachloride, Boron tetraoxide, trichlorine hexaiodide, 16) I, C, P/I/C, C,
P/I/C, P/I/C, C, I, I, C, P/I/C, P/I/C, C.
Balancing Chemical Equations:
2)Reactants, 3) products, 4) solid, liquid, gas, 5) 100g,
6) Mg+2HCl ---MgCl2 + H2
3Mg + N2 --- Mg3N2
Ba + 2HBr --- BaBr2 + H2
2BiCl3 + 3H2S --- Bi2S3 + 6HCl
Br2 + 2KI --- I2 + 2KBr
3Fe + 2O2 ---Fe3O4
2CaO + 5C ---2CaC2 + CO2
Bi2O3 + 3H2 ---2Bi + 3H2O
P4 + 6I2 ---4PI3,
Sn + 2NaOH --- Na2SnO2 + H2
C6H12O6 + 6O2 ---6CO2 + 6H2O,
2C8H18 + 25O2 ---16CO2 + 18H2O,
7) N, O, H, Cl, Br, I, F.