Question

Guys can anyone tell me the answers of these mcqs​

Answer 1

$\Large\bigstar{\underline {\red {\sf{Required \: answers : - }}}}$

1) Distribution of electrons in K , L and M shells of Argon

a] 2 , 8 , 8

b] 2, 8 ,7

c] 2 , 8 , 6

d] 2 , 8 , 5

K shell can acommodate 2 e⁻ , L shell can accomodate 8 e⁻ and M shell can accomodate 16 e⁻ . Argon has 18 e⁻ When 10e⁻ are situated in K and L shells . The remaining electrons move into M shell . This mean 2 e⁻ in K shell , 8e⁻ in L shell and 8e⁻ in M shell . Hence , Option(A) is the required answer .

$\rule{200}{1}$

2) When an atom achieves octet it does so by ,

a] losing electrons ⠀⠀⠀⠀⠀⠀⠀⠀b] gaining electrons

c] Sharing of electrons ⠀⠀⠀⠀⠀⠀d] any of the above

An atom can achive octet by sharing of electrons (or) by losing electrons (or) by gaining electrons . Hence , Option(d) is the required answer .

$\rule{200}{1}$

3) The number of neutrons in sodium and magnesium is

a] 12 and 12 respectively⠀⠀⠀⠀⠀⠀b] 11 and 12 resoectively

c] 11 and 11 respectively d] 12 and 11 respectively

(1) Number of neutrons = Mass number - Atomic number

⇒ Number of neutrons in Sodium = 23 - 11 = 12

and Number of neutrons in magnesium = 24 - 12 = 12

∴ The number of neutrons in Sodium and magnesium are 12 and 12 respectively.

Hence ,Option(a) is required answer .

$\rule{200}{1}$

4) Choose the incorrect statement

a] Isotope of Iodine is used in treatment of Goitre

b] Isotope of cobat is used in treatment of cancer

c] Isotope of uranium is used as fuel in nuclear reactor

d] Isotope of magnesium is used in formation of chlorophyll

Iodine () is used in treatment of Goitre .Uranium (235) is used as fuel in nuclear reactors .Cobalt is used in treatment of cancer (cobalt theraphy). We have got that Options (a) , (b) , (c) are correct . Option(d) is the required answer . (Since magnesium isn't used in formation of chlorophyll)

$\rule{200}{1}$

5) The average atomic mass of chlorine is

a] 35 u b] 35.5 u c] 35.25 u d] 35.75 u

Atomic mass of chlorine is approximately 35.5 u

Hence , Option(2) is the required answer .

$\rule{200}{1}$

6) The mass of an atom is entirely due to the

a] Protons b] neutrons

c] electrons d] Both (a) and (b)

Mass of an atom is entirely due to protons and Neutrons . Since elctrons have neglegibile mass

Hence , Option(d) is the required answer .

$\rule{200}{1}$

7) The outermost shell cannot have more than

a] 2 electrons b] 4 electrons

c] 18 electrons d] 8 electrons

The outermost shell cannot have more than 8 e⁻ .

Hence , Option(d) is the required answer .

$\rule{200}{1}$

8) Which of the following corrextly represents the configuration in the magnesium atom

a] 3 , 8 , 1 b] 2 , 8 , 2

c] 1 , 8 , 3 d] 8 , 2 , 2

K shell can acommodate 2 e⁻ , L shell can accomodate 8 e⁻ and M shell can accomodate 16 e⁻ . Magnesium has 12 e⁻ When 10e⁻ are situated in K and L shells . The remaining electrons move into M shell . This mean 2 e⁻ in K shell , 8e⁻ in L shell and 2e⁻ in M shell . Hence , Option(b) is the required answer .

$\rule{200}{1}$

9) Dalton's atomic theory succesfully explained

(i) Law of conservation of mass

(ii) Law of constant proportions

(iii) Law of radioactivity

(iv) Law of multiple propertions

a] (i) , (ii) , (iii) b] (i) , (iii) , (iv)

c] (ii) , (iii) , (iv) d] (i) , (ii) , (iv)

Dalton's atomic theory explains Law of conservation of mass , Law of constant proportions and Law of multiple proportions.

Hence , Option(d) is the required answer .

$\rule{200}{1}$

10) The number of electrons in an element X is 15 . The number of neutrons is 16. Which of the following is the correct represenation of element

a] X³¹₁₅ b] X³¹₁₆ c] X¹⁶₁₅ d] X¹⁵₁₆

The general representation ofvan elemnts is ,

$\rm X {}^{A} _{Z}$

Where ,

• A is mass number
• Z is atomic number

Number of protons = Number of electrons = Atomic number (neutral atom)

⇒ Z = 15

Mass number = Number of protons + Number of neutrons

⇒ Mass number = 15 + 16 = 31 = A

Then the representation of element is ,

$\rm {X}^{31}_{15}$

Hence , Option(a) is the required answer.

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Answer 2

Answer:

\Large\bigstar{\underline {\red {\sf{Required \: answers : - }}}}★

Requiredanswers:−

1) Distribution of electrons in K , L and M shells of Argon

a] 2 , 8 , 8

b] 2, 8 ,7

c] 2 , 8 , 6

d] 2 , 8 , 5

K shell can acommodate 2 e⁻ , L shell can accomodate 8 e⁻ and M shell can accomodate 16 e⁻ . Argon has 18 e⁻ When 10e⁻ are situated in K and L shells . The remaining electrons move into M shell . This mean 2 e⁻ in K shell , 8e⁻ in L shell and 8e⁻ in M shell . Hence , Option(A) is the required answer .

\rule{200}{1}

2) When an atom achieves octet it does so by ,

a] losing electrons ⠀⠀⠀⠀⠀⠀⠀⠀b] gaining electrons

c] Sharing of electrons ⠀⠀⠀⠀⠀⠀d] any of the above

An atom can achive octet by sharing of electrons (or) by losing electrons (or) by gaining electrons . Hence , Option(d) is the required answer .

\rule{200}{1}

3) The number of neutrons in sodium and magnesium is

a] 12 and 12 respectively⠀⠀⠀⠀⠀⠀b] 11 and 12 resoectively

c] 11 and 11 respectively d] 12 and 11 respectively

(1) Number of neutrons = Mass number - Atomic number

⇒ Number of neutrons in Sodium = 23 - 11 = 12

and Number of neutrons in magnesium = 24 - 12 = 12

∴ The number of neutrons in Sodium and magnesium are 12 and 12 respectively.

Hence ,Option(a) is required answer .

\rule{200}{1}

4) Choose the incorrect statement

a] Isotope of Iodine is used in treatment of Goitre

b] Isotope of cobat is used in treatment of cancer

c] Isotope of uranium is used as fuel in nuclear reactor

d] Isotope of magnesium is used in formation of chlorophyll

Iodine () is used in treatment of Goitre .Uranium (235) is used as fuel in nuclear reactors .Cobalt is used in treatment of cancer (cobalt theraphy). We have got that Options (a) , (b) , (c) are correct . Option(d) is the required answer . (Since magnesium isn't used in formation of chlorophyll)

\rule{200}{1}

5) The average atomic mass of chlorine is

a] 35 u b] 35.5 u c] 35.25 u d] 35.75 u

Atomic mass of chlorine is approximately 35.5 u

Hence , Option(2) is the required answer .

\rule{200}{1}

6) The mass of an atom is entirely due to the

a] Protons b] neutrons

c] electrons d] Both (a) and (b)

Mass of an atom is entirely due to protons and Neutrons . Since elctrons have neglegibile mass

Hence , Option(d) is the required answer .

\rule{200}{1}

7) The outermost shell cannot have more than

a] 2 electrons b] 4 electrons

c] 18 electrons d] 8 electrons

The outermost shell cannot have more than 8 e⁻ .

Hence , Option(d) is the required answer .

\rule{200}{1}

8) Which of the following corrextly represents the configuration in the magnesium atom

a] 3 , 8 , 1 b] 2 , 8 , 2

c] 1 , 8 , 3 d] 8 , 2 , 2

K shell can acommodate 2 e⁻ , L shell can accomodate 8 e⁻ and M shell can accomodate 16 e⁻ . Magnesium has 12 e⁻ When 10e⁻ are situated in K and L shells . The remaining electrons move into M shell . This mean 2 e⁻ in K shell , 8e⁻ in L shell and 2e⁻ in M shell . Hence , Option(b) is the required answer .

\rule{200}{1}

9) Dalton's atomic theory succesfully explained

(i) Law of conservation of mass

(ii) Law of constant proportions

(iii) Law of radioactivity

(iv) Law of multiple propertions

a] (i) , (ii) , (iii) b] (i) , (iii) , (iv)

c] (ii) , (iii) , (iv) d] (i) , (ii) , (iv)

Dalton's atomic theory explains Law of conservation of mass , Law of constant proportions and Law of multiple proportions.

Hence , Option(d) is the required answer .

\rule{200}{1}

10) The number of electrons in an element X is 15 . The number of neutrons is 16. Which of the following is the correct represenation of element

a] X³¹₁₅ b] X³¹₁₆ c] X¹⁶₁₅ d] X¹⁵₁₆

The general representation ofvan elemnts is ,

\rm X {}^{A} _{Z}X

Z

A

Where ,

A is mass number

Z is atomic number

Number of protons = Number of electrons = Atomic number (neutral atom)

⇒ Z = 15

Mass number = Number of protons + Number of neutrons

⇒ Mass number = 15 + 16 = 31 = A

Then the representation of element is ,

\rm {X}^{31}_{15}X

15

31

Hence , Option(a) is the required answer.

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