Science revision

•Charge – The coulomb

•Current – The ampere

•Potential Difference - The Volt

•Resistance - The ohm

•Resistivity – The ohm metre

•Energy – The joule

•Power – The watt

•Focal length – The metre

•Power of a lens – The dioptre.

Periods Groups

i. The horizontal rows of elements

in the modern periodic table are

called as periods.

ii. There are seven periods in the

modern periodic table.

iii. The period number indicates the

number of electronic shells present

in an atom of every element

belonging to that period.

iv. Elements show gradual variation

in chemical properties along a

period.

i. The vertical columns of elements

in the modern periodic table are

called as groups.

ii. There are eighteen groups in the


ii. There are eighteen groups in the


iii. The group number indicates the

number of electrons in the

outermost shell of an atom of

every element belonging to that

group.

iv. Elements belonging to a

particular group show strong

resemblance in their chemical

properties.

Mendeleev's periodic table Modern periodic table

i. In Mendeleev's periodic

table, elements were

arranged in an increasing

order of atomic weight.

ii. In Mendeleev's periodic

table there were 8 groups.

iii. In Mendeleev's periodic

table isotopes of same

elements were given different

positions.

iv. A correct position could

not be assigned to hydrogen

in the Mendeleev's periodic

table.

i. In Modern periodic table,

elements are arranged in an

increasing order of atomic

numbers.

ii. In modern periodic table,

there are 18 groups.

iii. In Modern periodic table

isotopes of same elements are

given same positions.

iv. Hydrogen has been placed

at the top of group I in


Inert gas elements Normal elements

i. In the atoms of Inert gas

elements all the shells are

completely filled including

the outermost shell.

ii. These elements are placed

in zero group (group 18) of


iii. These elements have

stable electronic

configuration and hence,

they are chemically inactive.

iv. Their valency is zero.

i. In the atoms of Normal

elements only the outermost

shell is incompletely filled.


in groups 1 and 2 on the left

side and 13 to 17 on the right

side of modern periodic table.

iii. These elements do not

have stable electronic

configuration and hence,

they are chemically active.

iv. They normally show one

type of valency.

Normal Elements Transition Elements

i. In the atoms of Normal

elements only the outermost

shell is incompletely filled.


in groups 1 and 2 on the left

side and 13 to 17 on the right

side of modern periodic table.

iii. They are included in s –

block and p – block of


iv. They normally show one

type of valency.

i. In the atoms of these

elements the last two shells

are incompletely filled.


in groups 3 to 12 in the

middle of the modern

periodic table.

iii. They are included in d –

block of modern periodic

table.

iv. They show variable

valency.

Transition elements Inner transition elements


elements the last two shells



in groups 3 to 12 in middle of

the modern periodic table.

iii. They are included in d –

block of the modern periodic

table.


elements the last three shells



in two additional rows (i.e.

lanthanides and actinides)

called series, placed at the

bottom of the modern

periodic table.

iii. They are included in f -

block of modern periodic

table.

s – block elements p – block elements

i. In modern periodic

table the groups 1 and 2

are included in s – block.

ii. These includes alkali

metals and alkaline earth

metals.

iii. They have 1 or 2

electrons in the last

shell.

i. In modern periodic

table the groups 13 to 17

and the zero group

elements are included in

p – block.

ii. These includes metals,

non – metals and

metalloids.

iii. They have 3 to 8

electrons in the last

shell.

Oxidation Reduction

i. The chemical

reaction in which

reactants gain

oxygen or lose

hydrogen is called

oxidation.

ii.A reducing agent

undergoes

oxidation.

i. The chemical

reaction in which

reactants gain

hydrogen or lose of

oxygen is called

reduction.

ii.An oxidising agent

undergoes

reduction.

Voltmeter Ammeter

i. A voltmeter is used to

measure the potential

difference between two

points.

ii.A voltmeter is

connected in parallel to

the conductor across

which the potential

difference is to be

measured.

iii.A voltmeter has a very

high resistance.

i. An ammeter is used to

measure the current in

a circuit.

ii.An ammeter is

connected in series

with the conductor, the

current through which

is to be measured.

iii.An ammeter has a

very low resistance.

Direct current Alternating current

i. Direct current flows

only in one direction.

ii.It cannot be used for

large scale of electricity

of household purpose.

iii.The frequency is zero.

i. Alternating current

reverses its direction

periodically with time.

ii.It is used in household

electrical appliances

such as an electric

heater, and electric

iron, a refrigerator, etc.

iii.The frequency of

alternating current in

India is 50 Hz.

Real image Virtual image

i. A real image is formed

when the light rays

starting from an object

meet after reflection or

refraction.

ii.It can be projected on a

screen.

iii.It is inverted with

respect to the object.

i. A virtual image is

formed when the light

rays starting from an

object appear to meet

after reflection or

refraction.

ii.It cannot be projected

on a screen.

iii.It is erect with respect

to the object.

Convex lens Concave lens

i. A convex lens has

its surfaces bulging

outward.

ii.It is thicker in the

middle than at the

edges.

iii.It can form a real

image as well as

virtual image.

i. A concave lens has

its surfaces curved

inward.

ii.It is thicker at the

edges than in the

middle.

iii.It can form only a

virtual image.

Metals Non – metals

i. Metals have a lustre.

ii. They are generally good

conductors of heal and

electricity.

iii.They are generally solids at

room temperature.

Exception : Mercury and

Gallium are liquids.

iv.Metals form basic oxides.

i. Non – metals have no

lustre. Exception : Iodine

and diamond.

ii. They are bad conductors of

heal and electricity.

Exception: Graphite

iii.They are generally gases

and solids at room

temperature. Exception :

Bromine is a liquid.

iv.Non – metals form acidic or

neutral oxides.

Roasting Calcination

i. In this process, the ore

is heated strongly in

the presence of air.

ii.In this process,

sulphide ore is

converted into metal

oxide.

iii.During this process

SO4 is given out.

i. In this process, the ore

is heated strongly in

the limited supply of

air.

ii.In this process,

carbonate ore is

converted into metal

oxide.

iii.During this process

CO2 is given out.

Saturated hydrocarbons Unsaturated hydrocarbons

i. In saturated hydrocarbons,

the carbon atoms are linked

to each other only by a

single covalent bonds.

ii. They contain only single

bond.

iii.These compounds are

chemically less reactive.

iv.Substitution reaction is a

characteristic property of

these hydrocarbons.

v. Their general formula is

CnH2n+2.

i. In unsaturated

hydrocarbons, the valencies

of carbon atoms are not

fully satisfied by single

covalent bonds.

ii. They contain carbon to

carbon double or triple

bonds.

iii.These compounds are

chemically more reactive.

iv.Addition reaction is a

characteristic property of

these hydrocarbons.

v. Their general formula is

CnH2n or CnH2n - 2.

Open chain

hydrocarbons

Closed chain

hydrocarbons

i. A hydrocarbon in

which the chain of

carbon atoms is not

cyclic is called the open

chain hydrocarbon.

ii.All aliphatic

hydrocarbons contain

open chains.

i. A hydrocarbon in

which the chain of

carbon atoms is

present in a cyclic form

or ring form is called

the closed chain

hydrocarbons.

ii.All aromatic

hydrocarbons contain

closed chains.

Stomach Small intestine

i. The stomach is the

broadest part of the

alimentary canal.

ii.Glands present in the

stomach wall produce

gastric juice.

iii.There is acidic

medium in the

stomach.

iv.Food gets partially

digested in the

stomach.

i. The small intestine is

the narrowest part of

the alimentary canal.

ii.Glands present in the

intestinal wall produce

intestinal juice.

iii.There is alkaline

medium in the small

intestine.

iv.Food gets completely

digested in the small

intestine.

External respiration Internal respiration

i. External respiration is also

called breathing.

ii. It is a physical process.

iii.It takes place in the

respiratory tract.

iv.The gaseous exchange

between external

atmosphere and the blood

takes place during external

respiration.

v. Oxidation of food does not

occur during external

respiration.

i. Internal respiration is also

called cellular respiration.

ii. It is a biochemical process.

iii.It takes place in the

mitochondria inside the

cell.

iv.The gaseous exchange

between the blood and

tissues occurs during inter

respiration.

v. Oxidation of food occurs

during internal respiration

releasing energy.

Arteries Veins

i. Arteries are blood vessels

which carry blood away from

the heart.

ii. Arteries are thick walled,

elastic blood vessels.

iii.The blood flow in arteries is a

rapid and is under higher

blood pressure.

iv.Arteries are situated deep

inside the body.

v. Arteries do not have valves.

vi.Except for pulmonary artery

all the arteries carry

oxygenated blood.

i. Veins are blood vessels which

carry blood towards the

heart.

ii. Veins are thin walled blood

vessels.

iii.The blood flow in veins is

slower and is under lesser

blood pressure.

iv.Veins are situated

superficially (Apparently) in

the body.

v. Veins have valves to prevent

back flow of the blood.

vi.Except for pulmonary vein all

the veins carry deoxygenated

blood.

Atria Ventricles

i. Atria are the upper

chambers of the heart.

ii. Atria are receiving

chambers as they receive

the blood.

iii.Atria have comparatively

thinner walls.

iv.Superior and inferior vena

cavae enter into right

atrium.

v. Pulmonary veins enter into

the left atrium.

i. Ventricles are the lower

chambers of the heart.

ii. Ventricles are driving

chambers as they sent the

blood the body.

iii.Ventricles have

comparatively thicker

walls.

iv.Pulmonary artery leaves

from right ventricle.

v. Aorta leaves from the left

ventricle.

Growth dependent

movements in plants

Growth independent

movements in plant.

i. Growth dependent

movements result in the

growth of plants.

ii. Growth dependent

movements are also called

tropic movements.

iii.Growth dependent

movements are in response

to light, water, chemical

stimuli, gravity, etc.

i. Growth independent

movements do not result in

the growth of plants.

ii. Growth independent

movements are also called

nastic movements.

iii.Growth independent

movements are in response

to touch or for capturing

prey or liberating the

seeds.

Central nervous

system

Peripheral nervous

system

i. The central nervous

system is located in

the central part of the

body.

ii. It is composed of

the brain and the

spinal cord.

i. The peripheral

nervous system is

located on the

peripheral parts of the

body.

ii. It is composed of

cranial nerves and

spinal nerves.

Cerebrum cerebellum

i. The cerebrum is the

part of the forebrain.

ii. The cerebrum is

concerned with thinking

and interpreting sensory

information.

iii. The cerebrum stores

memory.

i. The cerebellum is the

part of the hindbrain.

ii. The cerebellum is

concerned with

coordination of voluntary

movements and

maintaining the balance.

iii. The cerebellum does

not store memory.

Nervous control in

animal

Chemical control in

animal

i. Nervous control of the

body is done with the

help of neurons.

ii.Nervous system is

concerned with the

nervous control.

iii.Nervous impulses are

rapid.

iv.Nervous impulses are

of shorter duration.

i. Chemical control of the

body is done through

hormones.

ii.Endocrine system is

concerned with the

chemical control.

iii.Hormonal actions are

slower.

iv.Hormonal actions are

of longer duration, i.e.

long lasting.

Multiple fission Regeneration

i. Multiple fission is a

type of asexual

reproduction.

ii. In multiple fission,

division of the nucleus

takes place.

iii. Multiple fission is

carried out by the

repeated division of the

cytoplasm, e.g. Amoeba.

i. Regeneration cannot be

called reproduction

process. It is an

accidental process.

ii. In regeneration

division of the nucleus

may not take place.

iii. Regeneration is

carried out by specialized

cells in the body. e.g.

Planaria.

Asexual reproduction Sexual reproduction

i. Asexual reproduction is the

process in which only one cell

divides into two.

ii. Only one parent participates in

asexual reproduction.

iii.Only mitosis takes place at the

time of asexual reproduction.

iv. The process of fertilization and

formation of zygote do not take

place in asexual reproduction.

v. Somatic cells are involved in the

asexual reproduction.

i. Sexual reproduction is the

process in which two cells fuse

with each other.

ii. Two parents belonging to two

different sexes participate in the

sexual reproduction.

iii.Both mitosis and meiosis take

place at the time of sexual

reproduction.

iv. The process of fertilization and

zygote formation are the

important steps in sexual

reproduction.

v. Germ (Reproductive) cells are

involved in the sexual

reproduction.

Mitosis Meiosis

i. Mitosis is a type of cell division

that takes place in the somatic

cells.

ii. In mitosis the chromosome

number dies not change.

iii. It is also called equational

division as the cells produced

contain the same number of

chromosomes as that of the

parent cell.

iv. Mitosis occurs at the time of

asexual reproduction such as

binary fission. It also takes place

at the time of growth and sexual

reproduction.

i. Meiosis is a type of cell division

that takes place in the germ

cells.

ii. In meiosis the chromosome

number is reproduced to half.

iii. It is also called reduction

division as the cells produced

contain half the number of

chromosomes.

iv. Meiosis occurs at the time of

sexual reproduction during

gamete formation.

Testis Ovary

i. Testis is an essential

gonad in male.

ii.Testis produces

sperms.

iii.Testis secretes

testosterone.

iv.Testis is located

outside the body in the

scrotum.

v.Testis does not have

sperms at the time of

the birth of a boy.

i. Ovary is an essential

gonad in female.

ii.Ovary produces eggs.

iii.Ovary secretes

estrogen.

iv.Ovaries are located

inside the lower

abdomen.

v.Ovary has immature

eggs at the time of the

birth of a girl.

Monohybrid cross Dihybrid cross

i. Crosses involving a

single pair of alleles are

called monohybrid

crosses.

ii.Monohybrid crosses

yield a phenotypic ratio

of 3:1 in the F2

generation.

iii.Genes are not assorted

to form new

recombination of

characters.

i. Crosses involving two

pairs of alleles are

called dihybrid crosses.

ii.Dihybrid crosses yield

a phenotypic ratio of

9:3:3:1 in the F2

generation.

iii.Genes are assorted to

form new combinations

of characters.

Dominant characters Recessive characters

i. The characters that are

expressed in the F1

generation are called

dominant character.

ii. Tall habit and red colour of

the flower in pea plants are

dominant characters.

iii.Dominant character is

expressed in the presence of

one or both the dominant

genes.

iv.Dominant characters cannot

be masked by recessive

characters.

i. The characters that are not

expressed in the F1

generation are called

recessive characters.

ii. Dwarf habit and white

colour of the flower in pea

plants are recessive

characters.

iii.Recessive characters is

expressed only when both

the recessive alleles of a

gene are present.

iv.Recessive characters can be

masked by dominant

characters.

Phenotype Genotype

i. Phenotype refers to the

outward appearance of an

individual such as shape,

colour, sex, etc.

ii. Phenotype can be observed

directly in an individual.

iii.Individuals resembling

each other may or may not

have the same genotype.

iv.The phenotypic ratio

obtained in the F2

generation of a

monohybrid cross is 3:1.

i. Genotype refers to the

genetic composition of an

individual.

ii. Genotype can be

determined from ancestry

of an individual.

iii.Individuals possessing the

same genotype usually

have the same phenotypic

expression.

iv.The genotypic ratio

obtained in the F2

generation of a

monohybrid cross is 1:2:1.

Homologous organs Analogous organs

i. Homologous organs show

same structural plan.

ii. Functions performed by

the homologous organs are

different.

iii. Homologous organs

explain the common ancestry

in the evolution.

iv. Forelimb of a man, front

leg of a bull, wing of a bird,

fin of a whale are all

homologous organs.

1. Analogous organs show

different structure in

different animals.

ii. Functions performed by

the analogous organs are

always the same.

iii. analogous organs explain

the common adaptation due

to common habitats.

iv. Wing of a bird and wing of

an insect, tail fin of a lobster

and tail flukes of whale are

analogous organs.

Sucrose (Sugar) C12H22O11

Water H2O

Glucose (Fructose) C6H12O6

Iron Fe

Sulphur S

Iron Sulphide FeS

Carbon dioxide CO2

Carbonic acid H2CO3

Tricalcium Aluminate 3CaO.Al2O3

Concrete CaO.Al2O36H2O

Plaster of Paris CaSO4.H2O

Gypsum CaSO4.2H2O

Carbon (Coke) C

Calcium Carbonate CaCO3

Copper Sulphate CuSO4

Zinc Zn

Copper chloride CuCl2Silver Bromide AgBr

Potassium iodide KI

Cupric iodide CuI2

Potassium Chloride KCl

Potassium chromate K2CrO4

Barium sulphate BaSO4

Precipitate (yellow) BaCrO4

Potassium Sulphate K2SO4

Quicklime CaO

Zinc Sulphate ZnSO4

Aluminium Al

Aluminium Oxide (Alumina) Al2O3

Ethyl alcohol C2H5OH

Sodium ethoxide C2H5ONa

Methane CH4

Hydrochloric acid HCl

Magnesium Chloride MgCl2Aluminium chloride AlCl3Zinc Chloride ZnCl2Ferrous chloride FeCl2Sulphuric Acid H2SO4

Magnesium Sulphate MgSO4

Ferrous sulphate FeSO4

Sodium aluminate NaAlO2

Aluminium Hydroxide Al(OH)3

Zinc sulphide ZnS

Zinc oxide ZnO

Zinc carbonate ZnCO3

Carbon monoxide CO

Magnesium dioxide MgO2

Manganese dioxide MnO2

Iron (II) oxide Fe2O3

Cinnabar HgS

Mercuric oxide HgO

Cuprous Sulphide Cu2S

Cuprous oxide Cu2O

Nitric Acid HNO3

Magnesium nitrate Mg(NO3)2

Education

Science revision