chemistry ss 1 e learning notes first term scheme of …

CHEMISTRY SS 1

E – LEARNING NOTES

FIRST TERM SCHEME OF WORK

WEEK TOPICS/CONTENTS

1. INTRODUCTION TO CHEMISTRY

Career prospect in chemistry/application of chemistry

Scientific approach/method of discoveries

Effect of chemicals e.g drug abuse, poisoning, pollution, corrosion

Familiarization of laboratory apparatus

Drawing of laboratory apparatus

2. NATURE OF MATTER

Definition of matter

State of matter and changes in state of matter

Sublimation, evaporation etc

Properties of matter

Definition of physical and chemical properties

Difference between physical and chemical properties

3. ELEMENTS AND THEIR SYMBOLS

Definition of elements and the symbol of the first 30 elements

Classification of elements into the three state of matter e.g. sodium is

solid, neon is gas, and mercury is liquid

4. IUPAC NUMENCLATURE OF INORGANIC COMPOUND

Rules of IUPAC nomenclature

Concept of oxidation number and their uses

Conventional system of naming compound

5. STANDARD SEPERATION TECHNIQUE

Classification of substances

Filtration, evaporation, decantation, floatation, frostation

6. STANDARD SEPERATION TECHNIQUE condt

Crystallization, and fractional crystallization

Distillation and fractional distillation

Precipitation, magnetism, chromatography, centrifugation,

sublimation

Pure and impure substances

7. PARTICULATE NATURE OF MATTER

Concept of atoms, molecules and ions

Dalton’s atomic theory and its modification

8. CONSTITUENT OF ATOMS

Proton, electron and neutron

Arrangement of element in an atom

Atomic number, atomic mass, isotopes and calculation of relative

abundance of isotopes

9. STRUCTURE OF THE ATOM

Orbital and electrons structure of the atom

Rules and principles of filling the electrons

10. ELECRONIC CONFIGURATION OF ATOMS

Using energy levels and sub energy levels

CHEMISTRY @ OLASS, YABA.

SS 1 CHEMISTRY BY OTEGA OMOYIBO (TEGAMATICS) 1

Formation of ions and valency

Writing formulas of compound using valency

11. REVISION

12. EXAMINATION

INTRODUCTION TO CHEMISTRY

Objectives:

At the end of this topic, you should be able to:

1. Meaning of chemistry

2. Career prospects tied to chemistry

3. Application (i) Hospital (ii) Military (iii) Teaching (iv) Chemical and petrochemical industries.

4. Adverse effects of chemicals, drug abuse, poisoning, Corrosion and pollution.

5. Scientific methods.

6. list common laboratory apparatus/equipment and state their uses

MEANING OF CHEMISTRY

Chemistry is the study of matter: its structure, composition, properties, and the changes it undergoes.

Chemistry is one of the three main branches of pure science, the other two being physics and biology.

Chemistry which probes into the principles governing the changes that matter undergoes also deals with

the composition, properties and uses of matter. Some of the chemical changes which matter undergoes

include lighting a match, cooking, burning fire wood, making palm wine, rusting of nails, rotting of

leaves. Chemical changes are otherwise known as chemical reactions.

The knowledge of chemistry helps us to subject some matter to chemical processes thereby producing

some materials for our everyday use. Such materials include soaps, detergents, hair cream, perfumes,

oil, margarine and plastics among others.

There are three main branches of chemistry: inorganic, organic and physical chemistry.

Career prospects tied to chemistry

Career prospects tied to chemistry simply mean the job opportunities that are available for the students

with knowledge of chemistry. Such students can be employed with private and public sectors which

include: Teaching service, health service, food processing, petroleum and petrochemical industries,

manufacturing industry, extractive industry, Agriculture and Forestry.

(i) Teaching services: Concern those who teach in primary, secondary schools, colleges of

education and universities and even the laboratory assistants in schools and universities.

(ii) Health service: Involves pharmacists, biochemists, chemists, nutritionists, dieticians,

doctors, nurses, medical assistants, laboratory assistants and dispensers.

(iii) Food processing: Food processing involves food technologists and research chemists.

(iv) Petroleum and petrochemical industries –Involves application of the following people;

research chemists, chemical engineers and laboratory assistants.

(v) Extractive industry- Involves chemists, mining engineers and geologists.

(vi) Manufacturing Industry: This involves research chemists and chemical engineers in the

wide variety of manufacturing industries such as iron and steel works and cement factories.



(vii) Agriculture-Involves agricultural scientists, chemists, biochemists, and physiologists who

engaged in research to improve the quality and yield of crops and livestock, and to advise

farmers.

(viii) Forestry: Scientists engaged in research to preserve and improve forests and forestry

products.

APPLICATION/ USES OF CHEMISTRY

The knowledge of chemistry can be applied in the following areas; namely

1. Hospital: The knowledge of chemistry makes it possible for people to involve in chemical

research and technology which lead to production of medicine that we use today.

2. Military: The duty of the military is defence, to defend the territorial integrity of a nation or

state. Military cannot effectively do this without ammunition. Chemistry contributes to the

discovery and description of the theoretical bases for the behaviour of chemical substances such

as explosives used by the military. The gun powder used in the earliest guns was made by

mixing sulphur, charcoal, and potassium trioxonitrates (v), compounded by early chemists. The

manufacture of smokeless powder was based upon gun cotton, which is made from cotton fibers

soaked in a strong mixture of HNO3 and H2SO4.

3. Teaching- chemistry teachers and lecturers in secondary schools, polytechnics, colleges of

education and universities.

4. Chemical and petrochemical industries: Application chemists, research chemists, chemical

engineers, and laboratory assistants.

5. Space science: chemistry is not out in space exploration. In our efforts to gain more knowledge

of the other planets and outer space around us, special rockets called ‘space rocket’ are sent

into space. The first rocket was sent into space on October 4, 1957, by Russia. In July 1969,

Apollo II astronauts Neil Armstrong and Edwin Aldrin landed on the moon. These are made

possible by science and technology.

6. Agriculture: Agricultural scientists, chemists, biochemists, and physiologists engaged in

research to improve the quality and yield of crops and livestock, and to advise farmers.

ADVERSE EFFECTS OF CHEMICALS

The adverse effects of existence of chemistry

The existence of chemistry brought about the existence of chemicals. The adverse effects of

chemicals include: drug abuse, poisoning, corrosion and pollution.

(a) Drug Abuse: simply involves wrong usage of drugs. Some of these drugs include heroin,

cocaine and morphine which are used as addictive. Unscrupulous people produce and sell them

at huge profits. Drug addiction is a major problem in our society, especially among young

people. Many countries have imposed strict laws to control pollution and drug abuse. However,

the most effective control measure is education. We must use what we learnt to improve our

life and to control these abuses.



(b) Poisoning: This is where chemicals are used to poison the food we eat. This happens when the

chemicals used as addictive probably as preservative are added more than required or expired

in the food stuff where it was added, then instead of the food stuff bringing health to our body,

it turns to poison.

(c) Corrosion: Corrosion of iron can also be called rusting and requires the presence of water and

oxygen. Rusting can also be regarded as the slow deterioration of iron to iron (iii) oxide. This

iron (iii) oxide is permeable to both air and water and cannot protect the iron from further

corrosion of iron.

This rusting can be prevented by four methods.

(i) Application of protective coating.

(ii) Application of sacrificial metal.

(iii) Alloying.

(iv) Cathodic protection.

(d) Pollution: Chemical industries through the action of production pollute our environment as the

smoke enters into the air, and dirt of different kinds enter into the water thereby polluting the

entire environment. Specifically chemical wastes from factories and oil refineries and

radioactive wastes from nuclear plants pollute our environment. Oil spillage, exhaust from

motor vehicles, pesticides, fertilizers and acid rain have made our environment unclean and

endangered plant and animal life. Human health is also being threatened by environmental

pollution. Presently, chemists are trying to come up with a fuel that will reduce the air pollution

problem. They are also modifying chemical processes to recycle chemical wastes or change

them to harmless products which can be safely discharged into the surrounding.

SCIENTIFIC METHOD

This is the method the scientist used to produce different materials that exists because of chemistry.

In the light of this, the scientists use their senses to observe what is happening around them. From

a given set of observations, they see a certain pattern. This often leads to a problem which they try

to solve. They put forward a reasonable explanation or hypothesis and carry out appropriate

experiments to test it. Then, they carefully record their observations and the results of their

experiments.

If the experiments support the hypothesis, they carry out further investigations. They discuss the

hypothesis and results with other scientists in the field so that the hypothesis can be further tested.

When a hypothesis has been tested and found to be correct within the limits of available evidence.

It becomes a theory. A scientific law or principle is established only after the theory has been

extensively tested and proven true without any exception. If the experiments give negative results,

then the scientist goes back to his hypothesis and either modifies it or puts forward a new

hypothesis. This way of studying a problem is known as the scientific method. It is the very

foundation of all scientific discoveries.



COMMON LABORATORY APPARATUS AND THEIR USES

BEAKERS

Beakers are useful as a reaction container or to hold liquid or solid

samples.

They are also used to catch liquids from titrations and filtrates from

filtering operations.

CONICAL FLASK OR ERLENMEYER FLASKS

Conical Flasks are useful to contain reactions or to hold liquid samples.

They are also useful to catch filtrates.

TEST TUBES

Test Tubes are for holding small samples or for containing reaction mixture

TEST TUBE HOLDERS

Test tube holders are for holding test tubes when tubes should not be

touched

BURRETTES

Burrettes are for addition of a precise volume of liquid.

Note: The volume of liquid added can be determined to

the nearest 0.01 mL with practice.

PIPETTES

Pipette are used to dispense small quantities of liquids.

DROPPERS

Droppers are for addition of liquids drop by drop

MEASURING CYLINDERS

Measuring cylinder also known as graduated Cylinders are for measurement

of an amount of liquid.

Note: The volume of liquid can be estimated to the nearest 0.1 mL with practice.



VOLUMETRIC FLASKS

Volumetric Flasks are used to measure precise volumes of liquid

or to make precise dilutions.

GLASS FUNNELS

Glass Funnels are for funneling liquids from one container to another or for

filtering when equipped with filter paper.

BUNSEN BURNERS

Bunsen Burners are sources of heat.

HOT PLATES

Hot Plates can also be used as sources of heat when an open flame is not

desirable.

RETORD STAND WITH CLAMP

Retord stand with clamp are for holding pieces of glassware in place.

TONGS

Tongs are similar in function to forceps but are useful for larger items.

WASH BOTTLES

Wash bottles are used for dispensing small quantities of distilled

water.

Dilution mark



WATCH GLASSES

Watch glasses are for holding small samples or for covering beakers

or evaporating dishes.

WIRE GAUZE

Wire Gauze on a tripod stand or ring supports beakers to be heated by

bunsen burners

CLAY TRIANGLES

Clay Triangles are placed on a ring attached to a ring stand as a

support for a funnel, crucible, or evaporating dish.

SPATULA

Spatula is used to mix, spread, lift substances

Its used for scaping materials out of beakers etc

LABORATORY EQUIPMENT

BALANCES

Balances are used to determine the mass of a reagent or

object.

SPECTROPHOTOMETERS

Spectrophotometers are used to measure the absorbance or

transmittance of a liquid sample.

FUME CUPBOARD

Fume cupboards are used to ventilate noxious or harmful

gases.



COMMON LABORATORY TECHNIQUES

READING MENISCUS

In all volumetric glassware (pipette, burette, volumetric flasks, graduated cylinder, etc.), it is

necessary to read the level of a liquid. A liquid in a small-diameter container will form a meniscus or

curve at the surface of the liquid. Usually this meniscus curves

downward to a minimum at the center.

To read the level of the liquid properly, the eye should be at the

same level as the bottom of the meniscus. Sometimes a white

card or a white card will help a person to see the meniscus clearly.

For volumetric flasks and transfer pipette, the volume

of the glassware is exact when the bottom of the

meniscus is even with the etched line.

In a graduated cylinder or a burette, the volume is read

from the graduations etched on the glass.

NOTE: To read the volume correctly, visualize the distance

between the tenths of milliliter marks as divided into ten equal

amounts. The volume is then found by reading the number of

tenths of cubic centimeters or milliliters and estimating

hundredths of cubic centimeters or milliliters.

CARE OF REAGENT

The reagents used by all of the students can be contaminated by one careless student. Never put

anything back into the reagent bottle. A certain amount of liquid can be obtained in several ways:

1. Pour from the reagent bottle into a beaker and draw up the liquid into a pipette from the beaker.

2. Pour from the beaker into a graduated cylinder to within 0.1 ml of the desired amount, adding the

last drop with an eyedropper filled from a beaker.

3. Only use appropriately labeled spatulas for each reagent bottle. Pour the solid into a beaker, onto

weighing paper, or into a weigh boat. Never pour excess back into the bottle.

4. Reagents are to remain on the plastic on the center bench. This will

prevent spills and accidents from occurring at your work area

save time for everyone because all of the chemicals will be relatively easy to find in a central

location, and

Make clean-up easier if a spill does occur. When you are finished using a chemical, replace

the lid! A mix-up of lids could also contaminate an expensive chemical.

LIGHTING THE BUNSEN BURNER

Lighting the Bunsen burner - Make sure the rubber tubing is connected to the Bunsen

burner and the gas jet. Turn the gas valve until it is parallel to the gas jet. You should be

able to hear the gas flow. Use a flint striker to cause a spark and ignite the gas. Adjusting

the Bunsen burner - First, adjust the height of the flame using the gas valve at the bottom

of the burner. For a clean burning flame, more air is required than is available from the

gas exhaust. The air vents can be adjusted to produce an inner blue cone in the flame with

no yellow tip. Too little air produces a sooty, orange-yellow tipped flame that is quite

noisy. Too much air supply may cause the flame to separate from the burner and even

blow itself out. The ideal working flame is bluish-green with a light blue cone and it

burns quietly.



NATURE OF MATTER AND SEPARATION TECHNIQUES

OBJECTIVES


1. Define matter

2. Mention the various state of matter

3. Explain change of state

4. Distinguish between physical change and chemical change

5. Define element, compound, and mixture

6. State the difference between element compound and mixture

MATTER

Matter may be defined as anything that has mass and occupies space. Mass is a measure of quantity of

matter.

The mass of a body which is determined by means of an analytical balance is invariable, while the

weight of a body is not. Weight is the gravitational force of attraction exerted by the earth on a body.

The weight of a given body varies with the distance of that body from the centre of the earth. The weight

of a body is directly proportional to its mass as well as the earth's gravitational attraction.

STATE OF MATTER

Matter exists in three physical states which are:

1. Solid

2. Liquid and

3. Gas

NOTE: there is now a fourth and fifth state known as PLASMA and LIQUID CRYSTAL

PROPERTIES OF SOLID:

i. They are tightly packed or held together

ii. They have definite shape and definite volume

iii. They cannot move from one place to another, however they vibrate within a fixed position

iv. They have the lowest kinetic energy

v. They cannot be compressed

PROPERTIES OF LIQUID:

i. They are loosely packed or held together

ii. They have no definite shape, however they assume the shape of their container but definite

volume

iii. They can move from one place to another, however, their movement is limited

iv. Their kinetic energy is higher than that of solid but lower to that of gas

v. They cannot be compressed

PROPERTIES OF GAS:

i. They are more loosely packed or held together

ii. They have no definite shape and no definite volume

iii. They can move from one place to another without limitation

iv. They have the highest kinetic energy

v. They can be compressed, because they fill their container



CHANGE OF STATE

The three states of matter of matter are interchangeable, that is, a particular state of matter can be

converted or changed to another state. For example, when a matter in its solid-state changes to liquid,

it is said to have undergone melting. The diagram below illustrates the change of state.

PROPERTIES OF MATTER

There are two properties of matter which are:

1. Physical properties

2. Chemical properties

Physical properties are the properties associated with physical changes. These properties are

the intrinsic properties of matter because they can be observed without causing any change in

the chemical composition of the matter. Examples include:

i. Density

ii. Colour, taste and smell of a substance

iii. Physical state

iv. Melting point

v. Boiling point

vi. Hardness and

vii. Electrical conductivity

Chemical properties are the properties associated with chemical changes. These properties are

the extrinsic properties of matter since they are the changes that matter undergo. Examples

include:

i. Corrosion

ii. Burning etc.

PHYSICAL CHANGES

A physical change is one which is easily reversed and produces no new substances. Examples incude:

i. The dissolution of common salt in water is a physical change because no new substance is

formed and the salt can be recovered by evaporating the solution to dryness.

ii. Changes in state: such as

the melting of a solid, e.g., ice, candle wax etc.

the liquefaction of gases to liquids

the freezing and vaporization of a liquid



iii. Physical means: such as filtration, evaporation, distillation, sublimation and crystallization may

be used to separate the components of a mixture, but a substance that was not present in the

original mixture is never produced by these means.

iv. Magnetization and demagnetization of iron rods.

CHEMICAL CHANGES

Chemical change is a change which is not easily reversed and in which new substances are formed.

Physical means cannot be used to separate the components. Examples include:

i. Burning of substances e.g., wood

ii. Addition of water to calcium oxide (quick lime)

iii. Burning of magnesium ribbon in Bunsen flame. It burns with a bright white flame to form white

ashes of magnesium oxide.

iv. The rusting of iron in moist air

v. Reaction of metals and calcium trioxocarbonate (IV) with dilute acids

vi. Reaction of some metals with water to produce the corresponding alkalis and hydrogen gas.

DIFFERENCES BETWEEN PHYSICAL AND CHEMICAL CHANGES

PHYSICAL CHANGES CHEMICAL CHANGES

1. It is easily reversible it is not easily reversible

2. It produces no new substances New substances are produced

3. There is no change in the mass of substance

involved

There is change in the mass of substance involved

4. It does not involve any great heat changes except

latent heat changes which occur during change of

state e.g., heat of dissolution, latent heat of fusion

and vaporisation

A considerable amount of heat change is involved,

e.g., explosion of coal gas or hydrogen with air.

CLASSIFICATION OF MATTER

There are three classifications of matter, they include:

1. Elements

2. Compound and

3. Mixture

ELEMENTS

An element is a substance which cannot be split into simpler units by ordinary chemical process.

Elements constitute the building block of all other substance.



There are 118 known elements. Ninety of them, occur naturally, while the rest are made artificially in

the laboratory. Elements are arranged according to their atomic number.

CLASSIFICATIONS OF ELEMENT

Elements are classified into

i. Metals

ii. Metalloids and

iii. Non-metals.

NOTE: The metalloid are those that share the properties of both the metals and non-metals. They are

also known as semi-metals.

ELEMENT, PROPERTY AND EXAMPLES

Elements Property Examples

Metals Good conductor Iron, Tin, Lead, Zinc etc.

Metalloids Semi-Conductor of electricity Silicon, Boron, Arsenic,

Tellurium etc.

Non-metals Non-Conductor of electricity Oxygen, Chlorine, Hydrogen,

Argon, Bromine etc.

DIFFERENCES BETWEEN PHYSICAL PROPERTIES OF METALS AND NON-METALS

Metals Non-Metals

All metals except mercury are generally solids under

ordinary condition

Non-metals may be gases, e.g Oxygen, Hydrogen,

Argon etc.

Or liquid, e.g., bromine,

Or solid, e.g., carbon, sulphur etc.

Metals have high melting point and boiling point Non-metals except carbon have low melting and

boiling points.

Metals are good conductors of heat and electricity,

e.g. aluminium.

Non-metals except graphite are poor conductors of

heat and electricity

Metals are malleable i.e. can be hammered into

different shapes and are ductile, i.e. can be drawn

into thin wire.

Non-metals are brittle, i.e., cannot be hammered.

They possess characteristics lustre They do not possess characteristic lustre except

carbon.

They exist as crystal lattice held by strong metallic

bonds

Non-metals except diamond exist as covalent

molecules held together by weak forces.



COMPOUNDS

A compound is a substance formed when two or more different elements are chemically joined together.

A compound is formed as a result of a chemical change, and it is a new substance with different

properties from the substance(s) from which it was formed.

The component elements of a compound are present in a fixed ratio by mass. For example, water is a

compound formed a result of chemical reaction among the compound elements, hydrogen and oxygen

in the ratio of 2 : 1 respectively

NOTE: There are two types of pure substance namely:

(i) An element

(ii) A compound:

Compounds Components Elements

Water, (H2O),

Sodium hydroxide, (NaOH)

Sodium chloride (NaCl)

Glucose,(C6H12O6)

Ethanol,(C2H5OH)

Calcium hydroxide, [Ca(OH)2]

Soap (C17H35COONa)

Sodiumtrioxocarbonate(IV)decahydrate,

(Na2CO3.10H2O)

Hydrogen, Oxygen

Sodium, Oxygen and Hydrogen.

Sodium, Chlorine.

Carbon, Hydrogen, and Oxygen.

Carbon, Hydrogen, and Oxygen.

Calcium, Oxygen and Hydrogen.

Carbon, Hydrogen, Oxygen and Sodium.

Sodium, Carbon, Oxygen and Hydrogen

MIXTURES

A mixture is a substance formed when two or more constituents are physically joined together. The

constituents of mixtures can be elements or compounds or both, and be separated by physical means,

since they are not chemically combined.

The constituents of a mixture retain their individual identities because their physical and chemical

properties are not changed by simple mixture.

TYPES OF MIXTURES

A mixture may be

Homogeneous or

Heterogeneous.



Homogeneous mixtures is a uniform mixture, called solution and the single phase in which a solution

occurs may be gaseous, liquid or solid. A solution is made up of more than one substance, one being

uniformly dispersed in the other.

Heterogeneous mixture is a non-uniform mixture.

Pure substances are homogeneous materials that have fixed compositions and invariable intrinsic

properties.

EXAMPLES OF MIXTURES AND THEIR CONSTITUENTS

Mixtures Constituents

Air Oxygen, Carbon(IV)oxide, Nitrogen, Rare

gases, Dust and Moisture

Soil Sand, Clay, Humus, Water, Air and Mineral

salts.

Urine Urea, Water, Mineral salts.

Palm wine Water, Sugar, Alkanol, Mineral salts,

Vitamins, Yeast, Proteins

Milk Water, Sugar, Fat, Proteins, Mineral salts and

Vitamins

Sea water Water, Mineral salt, Bacterial, Remains of

organic matter

Blood

Water, proteins, Fat, Oil, Sugar, Mineral Salts

Vitamins, Hormones, Enzymes, Blood cells,

haemoglobin.

Petroleum Petrol, Heavy oil, Gas oil, Kerosene, Naphtha,

Bitumen, gas, etc.

Bronze Copper and Tin.

DIFFERENCES BETWEEN MIXTURES AND COMPOUNDS

Mixtures Compounds

1. It may be homogeneous or heterogeneous. It is always homogeneous

2. The constituents are not chemically bound

together and cannot be separated by physical

separated by physical means.

The component elements are chemically

bound together and can be easily means.



3. The constituents can be together in any ratio

by mass. Hence, a mixture cannot be

represented by a chemical formula

The component elements are present in a fixed

ratio by mass. Hence, a com pound can be

represented by a chemical formula

4. The properties of mixture are the sum of

those of its individual constituents.

The properties of a compound differ entirely

from those of its component elements.

5. Mixture is not usually accompanied by

external effects such as explosion, evolution

of heat or volume change.

Usually accompanied by one or more of these

effects

NAMING OF COMPOUND USING IUPAC NOMENCLATURE

OBJECTIVES


1. Define valency, radical and oxidation number

2. Use the knowledge of valency and radical to write the formula od an inorganic compound

3. Name an inorganic compound

VALENCY/OXIDATION NUMBER

VALENCY can be defined as the combining power of an element or radical.

OXIDATION NUMBER can be defined as the electrical charge it appears to have as determined by a

set of arbitrary rules

NOTE: Oxidation number and valency are similar in a way but the striking difference is that, valency

carries no sign of charge but oxidation number either carries a positive or negative charge. Metals carries

a positive sign while n on-metals carries negative

HOW TO CALCULATE OXIDATION NUMBER

The IUPAC system uses oxidation numbers in naming compounds. The following rules are employed

in calculating oxidation number

RULES FOR DETERMINING OXIDATION NUMBER

1. The oxidation number of all element/molecules in their free state is zero. e.g., Na, Cl2, Mg, P4

etc

2. The oxidation number of simple ions has the same size and sign as the charge of the ion. e.g.,

Na+, Mg2+, Cl- and S2- are +1, +2, +3, -1 and -2 respectively

3. The algebraic sum of oxidation number of all elements in a compound is zero. e.g., MgCl2 = 0,

H2SO4 = 0

4. The algebraic sum of the oxidation number of radicals has the size and sign as the charge of the

radical. e.g., SO42-, NH4

+, OH-, ClO3-, has oxidation number of -2, +1, -1 and -1 respectively

NOTE: in most compound, the oxidation number of oxygen is -2, (except in peroxide where it is -1)

while the oxidation number of hydrogen is +1 (except in hydride where it is -1)



EXAMPLE:

1. Calculate the oxidation number of manganese in KMnO4

2. State the change in the oxidation number of Cu from the reaction below:

Cu → Cu2+

State the change in the oxidation number of Cu from the reaction below:

8H+ + MnO4- → Mn2+ + 4H2O

CLASS ACTIVITY

Find the oxidation number of the following marked element

i. H𝑁O3

ii. K2𝐶𝑟2O4

iii. [𝐹𝑒(CN)6]4-

iv. Na2𝑆O4

v. H2𝑆O4

vi.

The table below shows the oxidation number and valency of the first 20 elements

Element Symbol Oxidation

number

Valency

Hydrogen

Helium

Lithium

Beryllium

Boron

Carbon

Nitrogen

Oxygen

Fluorine

Neon

Sodium

Magnesium

Aluminium

Silicon

Phosphorus

H

He

Li

Be

B

C

N

O

F

Ne

Na

Mg

Al

Si

P

+1

0

+1

+2

+3

+2 or +4

-3 or +5

-2 or +6

-1 or +7

0

+1

+2

+3

+2 or +4

-3 or +5

1

0

1

2

3

2 or 4

3 or 5

2 or 6

1 or 7

0

1

2

3

2 or 4

3 or 5



Sulphur

Chlorine

Argon

Potassium

Calcium

S

Cl

Ar

K

Ca

-2 or +6

-1 or +7

0

+1

+2

2 or 6

1 or 7

0

1

2

RADICALS

Radicals are groups of atom carrying and electrical charge and function as a single unit.

The table below shows some radicals, names oxidation number and valency

Name Formula Oxidation

number

Valency

Trioxonitrate (V)

Trioxochlorate (V)

Tetraoxomanganate (VII)

Hydroxide

Hydrogen trioxocarbonate (IV)

Hydrogen tetraoxosulphate (VI)

Trioxocarbonate (IV)

Tetraoxosulphate (VI)

Trioxosulphate (IV)

Tetraoxophosphate (V)

Ammonium

𝑁𝑂3−

𝐶𝑙𝑂3−

𝑀𝑛𝑂4−

𝑂𝐻−

𝐻𝐶𝑂3−

𝐻𝑆𝑂4−

𝐶𝑂32−

𝑆𝑂42−

𝑆𝑂32−

𝑃𝑂43−

𝑁𝐻4+

-1

-1

-1

-1

-1

-1

-2

-2

-2

-3

+1

1

1

1

1

1

1

2

2

2

3

1

ASSIGNMENT: Mention 7 other radicals, there formulas, oxidation number and valency

WRITING CHEMICAL FORMULAE

With the students' knowledge of the symbols for some elements, the oxidation numbers assigned to

them in their combined states and the valency, they are now better equipped to write the correct

formulae for some chemical compounds.



The following rules will guide the students in doing so:

Write the symbols for the element and radicals.

Write the oxidation valencies above and to the right of the symbols.

Rewrite the symbols, exchanging the valencies and write the number below and to the right of

the symbol

The number of atoms of the component elements in the formula must be written as a numerical

subscript after the element concerned. If a radical occurs more than once it must be enclosed

with a parentheses

Example: By applying the rules, the formulae of the following compounds can be written:

i. Sodium hydroxide

ii. Magnesium chloride

iii. Calcium trioxonitrate (V)

iv. Aluminium tetraoxosulphate (VI)

v. Sodim trioxocarbonate (IV)

vi. Ammonium tetraoxosulphate (VI)

vii. Calcium hydroxide

viii. Potassium trioxonitrate (V)

ix. Hydrogen tetraoxophate (V)

x. Potassium trioxochlorate (V)

xi. Ammonium chloride

xii. Magnesium oxide

xiii. Aluminium oxide

xiv. Sodium nitride

xv. Sodium floride

NAMING OF INORGANIC COMPOUND:

Inorganic compounds comprises of cations and anions.

The cations are usually named first before the anions

Cations are named the way they appear e.g, Na is named sodium, Ca is named calcium etc

There are ways we name anions: if the anion ends with ygen, ine the name ends with ide. For

example, oxygen is named oxide, chlorine is named chloride etc

Radicals are always names the way they appear in the radical table above

Binary compounds. Binary compounds contain two elements only. The metal is named first,

followed by the name of the second element ending with –ide. If the metal is one that has

variable valencies, the valency exhibited will be written in Roman numeral examples are given

below:

Name of compounds

Formula Conventional Name IUPAC Name

Na2O Sodium oxide

Fe2O3 Iron (III) oxide



CO Carbon monoxide Carbon (II) oxide

CO2 Carbon dioxide Carbon (IV) oxide

N2O Nitrous oxide Dinitrogen (I) oxide

EXAMPLE:

Name the following compound: NaOH, CaSO4, Al2O3, CaCl2, NH4NO3

Solutions:

NaOH = Sodium hydroxide

CaSO4 = Calcium tetraoxosulphate (VI)

Al2O3 = Aluminium oxide

CaCl2 = Calcium chloride

NH4NO3 = Ammonium trioxonitrate (V)

CLASS ACTIVITY

Name the following compound:

1. Na2CO3

2. K2SO4

3. H2O

4. H2SO4

5. Ca(NO3)2

6. NaCl

7. KF

8. NH4Cl

9. (NH4)2SO4

10. MgO

11. Al(NO3)3

12. KOH

13. HNO3

14. HCl

15. CaO

chemistry ss 1 e learning notes first term scheme of …

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