Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 5

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11th CBSE

IMPORTANT

Earn 100

In which one of the following pairs, the two species are both isoelectronic and isotopic ? (Atomic numbers : $Ca = 20, Ar = 18, K = 19, Mg = 12, Fe = 26, Na = 11) .$

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Important Questions on Structure of Atom

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 6

The group having isoelectronic species is

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 7

A standing wave in a string

35 cm

long has a total of six nodes including those at the ends. Hence, wavelength of the standing wave is

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 8

For hydrogen atom, Rydberg constant

(R_{H})

is

x m^{- 1}

. Then for

{He}^{+}

ion, the corresponding value of this constant will be

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 9

The energies

E_{1}

and

E_{2}

of two radiations are

25 eV

and

50 eV

respectively. The relation between their wavelengths, i.e.,

λ_{1}

and

λ_{2}

will be

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 10

The value of Planck's constant is

6.63 x 10^{- 34} Js

. The speed of light is

3 x 10^{17} nm s^{- 1}

. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of

6 x 10^{15} s^{- 1} ?

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 11

Calculate the wavelength of the light required to break the bond between two chlorine atoms in a chlorine molecule. The

Cl - Cl

bond energy is

243

kJ {mol}^{- 1}

(h = 6.6 \times 10^{- 34} Js, c = 3 \times 10^{8} {ms}^{- 1}

,

Avogadro' s number = 6.02 \times 10^{23} {mol}^{- 1})

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 13

When the frequency of the incident radiation on a metallic plate is doubled, KE of the photoelectrons will be

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 2 - Structure of Atom>Competition Focus>Q 14

Photoelectric emission is observed from a metal surface with incident frequencies

v_{1}

and

v_{2}

where

v_{1} > v_{2}

. If the kinetic energies of the photoelectrons emitted in the two cases are in the ratio

2 : 1

, then the threshold frequency

v_{0}

of the metal is