If two elements X and Y have 3 and 6 electrons in its outermost s

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 Multiple Choice QuestionsMultiple Choice Questions

341.

According to Bohr's theory, which of the following correctly represents the variation of energy and radius of an electron in nth orbit of H-atom?

  • En  1n2, r 1n2

  • En 1n2, r n2

  • En n2, r n2

  • En n, r 1n


342.

The correct set of quantum numbers for the unpaired electron of a chlorine atom is :

  • 2 , 0 , 0 , +12

  • 2 , 1 , -1 , +12

  • 3 , 1 , -1 , ±12

  • 3 , 0 , 0 , ±12


343.

Number of electron in one molecule of NH3 :

  • 17

  • 34

  • 7

  • 10


344.

The value of magnetic quantum number for l = 3 :

  • 0 , +1 , +2 , +3

  • 0 , ± 1 , ± 2 , ± 3

  • -1 , -2 , -3

  • ± 1 , ± 2 , ± 3


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345.

Assertion : H2S is stronger acid than PH3.

Reason : S is more electronegative than P, conjugate base HS- is more stable than H2P-.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


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346.

If two elements X and Y have 3 and 6 electrons in its outermost shell , then the molecular formula of compound formed by the combination of X and Y :

  • XY

  • X3Y

  • X2Y

  • X2Y3


D.

X2Y3

X has 3 electrons so it forms X3+ ion while Y has 6 electron in its outermost shell therefore it forms Y ion .

X3+ + Y2-  X2Y3


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347.

The probability of finding of three unpaired electron in nitrogen atom is defined by :

  • Aufbau's principle

  • Uncertainty principle

  • Pauli's principle

  • Hund's rule


348.

α-particles can be detected by using

  • thin aluminium sheet

  • barium sulphate

  • zinc sulphide screen

  • gold foil


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349.

In a decay process XZA changes into YZ-1A. Which process is this?

  • β-decay

  • β+ decay

  • α- decay

  • γ- decay.


350.

Which of the following pairs represent isotones?

  • As3377,Se34 78

  • Pt78195,Os76190

  • Ag47108,Cd48112

  • Hf72178,Ba56137


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