West Bengal Class 8 English Medium Science Solution Chapter 2.2 Structure of Matter

On this Page we have given West Bengal Class 8 English Medium Science Solution Chapter 2.2 Structure of Matter Question and Answer for our Students of West bengal Class 8 English Medium. Hope this following Question Answer will help our Students.

West Bengal Class 8 | Science | Structure of Matter

 

MCQ

1) Who was the person who coined the term Atmos ?

a ) leucippus  b) Democritus c) Kanada d) John Dalton

Ans. Democritus

2) The atomic theory proposed by John Dalton states that

a ) an atom is the smallest divisible particle of an atom

b ) atoms of different elements have same mass

c ) atoms of different elements have same chemical properties

d ) all of them

Ans. An atom is the smallest divisible particle of an atom

3) During a chemical change atoms of different elements combine in a ratio of ________ numbers.

a ) integers b) whole c) decimal d) rational

Ans. Whole

4) protons and neutrons are both nearly ______ times heavier v than electrons

a ) 1000 b) 1500 c) 2000 d) 2500

Ans. 2000

5) An atoms is electrically neutral because

a ) it has same number of electrons and protons

b ) it has same number of electrons and neutrons

c) it has same number of neutrons and protons

d) the reason in unknown

Ans. It has same number of electrons and protons

6) One of them is not a conclusion of Rutherford  Atomic model

a ) most of the space inside an atom is empty

b ) it’s whole mass lies at the centre

c) electron move around in an orbit

d ) the positive charge is distributed throughout the atom

Ans. The positive charge is distributed throughout the atom

7) It’s the force which prevents the protons from scattering away

a ) cohesive b) nuclear c) adhesive d) repulsive

Ans. Nuclear

8) The total number of ____ in an atom is called the Atomic number

a ) protons b) electrons c) neutrons d) both protons and neutrons

Ans. Protons

9) The total number of protons and neutrons in an atom is called it’s

a) atomic weight b) subatomic weight c) atomic mass d) subatomic mass

Ans. Atomic mass

10) An atom has 7 protons, 7 neurons and 7 electrons ,so it’s mass and atomic number will be

a ) 14 , 7

b) 7, 14

c ) 7 , 7

d) 14 , 14

Ans. 14 , 7

11) Name the atom having an atomic mass of 6 and atomic number of 3

a ) Sodium b) Magnesium c) Chlorine d) lithium

Ans. Lithium

12) The atoms of same element having unequal number of neutrons are known as

a ) isomers b) isotopes c) isobars d) isolobes

Ans. Isotopes

13) Atoms of different elements having equal _____ are known as isobars of one another

a ) protons b) electron c) atomic number d) atomic mass

Ans. Atomic mass

14) The diameter of an atom is about ___ times larger than the nuclear diameter

a ) 10² b) 10³ c) 10⁵ d) 10⁷

Ans . 10⁵

15) In Which states of matter the molecules are always in a constant motion

a ) solids b ) liquid c) gas d ) both liquid and gas

Ans. Both liquid and gas

16) Gases have no definite shape and volume because

a ) the intermolecular space is large

b ) the particles are always in constant motion

c) Both a and b

d ) intermolecular force of attraction is strong

Ans.  Both a and b

17) The matter can change its state if it’s subjected to a

a ) increase in temperature

b ) decrease in temperature

c) both a and b

d ) physical damage

Ans. Both a and b

18) The very hot gaseous state comprising of separated electrons and nuclei is termed as

a ) plasma  b) grey matter c) dark matter d) fusion

Ans. Plasma

19) The common trait between salt, quicklime, caustic soda and slaked lime Is

a ) they are all sublime materials

b) they are composed of molecules

c ) they are composed of ions

d) they are present in liquid states

Ans. They are composed of ions

20) Which state is not true about salt

a ) it melts at 800⁰C

b ) it can conduct electricity in molten state

c) electrons conduct electricity in molten state

d ) all of them are false

Ans. Electrons conduct electricity in molten state

21) The compounds having made up of a metal and a non metal is known as

a ) bi-compound

b) ionic compound

c) hetrogenic compound

d) multi-compound

Ans. Ionic compound

22) Identify the metals which have more than one type of cations

a ) lead b) zinc c) iron d) alluminium

Ans. Iron

23) more than ___ atom must combine to from a radical

a ) 5 b) 4 c) 3 d) 1

Ans. 1

24) name the radical having the chemical formulae of OH—

a ) Hydroxyl b) Hydroxide c) Oxyhydrogen d) Oxyhydroxyl

Ans. Hydroxide

25) Choose the correct central atom, valency of central atom and number of covalent bonds for water

a ) O , 2 , 2

b) H , 1 , 2

c) O , 1 , 2

d) H , 2 , 2

Ans. O, 2 , 2

 

Short answer questions – 

(1) What is an atom made up of ?

→Atoms are made up of three smaller particles called as protons, neutrons, and electrons.

(2) What is mass number ?

→Total number of protons and neutrons in an atom called as mass number.

(3) What is atomic number ?

→The total number of protons in an atom is called as atomic number.

(4) What are isotopes ?

→Atoms of same element having unequal number of neutrons are called as isotopes.

(5) How many numbers of protons present in sodium atom ?

→Eleven

(6) What are isobars?

→Atoms of different elements that have equal mass number are called as isobars.

(7) What happens when we increase the temperature of solid ?

→When increase the temperature of solids they are converted into liquid state with increasing kinetic energy.

(8) What happens when increase the temperature of liquids ?

→By increasing the temperature of liquids, they are converted into its vapors state and it is called as boiling.

(9) What is known as crystal ?

→A grain of salt with definite geometrical shape is called as crystal.

 

(10) What is melting point of sodium chloride ?

→Sodium chloride melts at the temperature of 800 degree Celsius.

(11) Define ions.

→ Charged atoms are known as ions.

(12) What are the cations ?

→Positively charged ions are called as cations .

(13) Define anions.

→Negatively charged ions are called as anions.

(14) Could ions conduct electricity through molten salt?

→Yes , ions can conduct electricity.

(15) Give the chemical formula of zinc sulfide.

→ ZnS

(16) What is radical ?

→When more than one atom combine to form ion called as radical.

(17) Give two examples of radicals.

  • Carbonate radical
  • Ammonium radical

(18) What are the covalent compounds ?

→Covalent compounds are the compounds formed by sharing of electrons with each other.

(19) Give two examples of covalent compounds ?

  • Methane
  • Ammonia
  • Carbon dioxide

 

(20) Give the formula of cupric oxide.

→ Cupric oxide-    CuO

(21) State the formula of ferric chloride.

→Ferric chloride  – FeCl3

(22) State the cation and anion present in Mercurous chloride.

→ Cation  –  Hg

Anion – Cl

(23) What is plasma ?

→Hot gaseous state comprising of separated electrons and nuclear is called as plasma.

(24) How atoms are arranged in solid state ?

→ Atoms in a solid state are arranged in relatively ordered state and close to one another.

(25) Give one physical property of solid ?

→Solids have their own definite shape and volume.

(26) How items are arranged in a liquid state ?

→Atoms in liquid state are arrange relatively in a disorder state compare to solids.

(27) Give one physical property of liquid ?

→Liquids have no definite shape but it does have definite volume.

(28) How molecules are present in gaseous state ?

→ Molecules moving randomly with different speed in gaseous state.

(29) Give property of gaseous state.

→Gases have no fix volume and shape.

(30) Neutrons are electrically ________

→ Neutrons are electrically neutral.

Also See: Previous Chapter Chemical Reactions Question Answer

Updated: May 29, 2023 — 2:27 pm

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