The combining capacity of an element is called valency. The valence electrons determine the combining capacity of an atom. The number of bonds that an atom can form as part of a compound is expressed by the valency of the element. For example- The valency of hydrogen is 1, oxygen is 2, carbon is 4, etc.

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Explain the difference between valence electrons and covalency of an element.

Important Questions on Structure of The Atom

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Science>Chemistry>Structure of The Atom>Valency

The pair of valencies exhibited by tin

(Sn)

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Science>Chemistry>Structure of The Atom>Valency

Valence electron in

{Cl}^{-}

ions is

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Science>Chemistry>Structure of The Atom>Valency

The half-life of a radioisotope is

4

hours. If the initial mass of the isotope was

200 g

, the mass remaining after

24

hours undecayed

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Science>Chemistry>Structure of The Atom>Valency

A unit cell of calcium fluoride has four calcium ions. The number of fluoride ions in the unit cell is

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Science>Chemistry>Structure of The Atom>Valency

Hydrogen contains three types of atoms (

{}_{1}^{1}H

protium,

{}_{1}^{2}H

deuterium,

{}_{1}^{3}H

tritium). These atoms are

EASY

Science>Chemistry>Structure of The Atom>Valency

In calcium fluoride, having the fluorite structure, the coordination numbers for calcium ion

(C a^{2 +})

and fluoride ion

(F^{-})

are

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Science>Chemistry>Structure of The Atom>Valency

Which one of the following is cation

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Science>Chemistry>Structure of The Atom>Valency

The cubic unit cell structure of a compound containing cation $M$ and anion $X$ is shown below. When compared to the anion, the cation has smaller ionic radius. Choose the correct statement(s).

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Science>Chemistry>Structure of The Atom>Valency

The following is the correct decreasing order of the ionic radii-

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Science>Chemistry>Structure of The Atom>Valency

The number of protons in one atom of an element

X

8

. What will be the number of electrons in its ion

X^{- 2}

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Science>Chemistry>Structure of The Atom>Valency

The radius of

K^{+}

133 pm

and that of

{Cl}^{-}

181 pm

. The volume of the unit cell of

KCl

expressed in

10^{- 22} {cm}^{3}

is:

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Science>Chemistry>Structure of The Atom>Valency

A positively charged body has

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Science>Chemistry>Structure of The Atom>Valency

The barrier potential of a p-n junction depends on:

(a)

type of semi-conductor material

(b)

amount of doping

(c)

temperature
Which one of the following is correct?

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Science>Chemistry>Structure of The Atom>Valency

Consider an ionic solid

MX

, with

NaCl

structure. Construct a new structure

(Z)

, whose unit cell is constructed from the unit cell of

MX

, following the sequential instructions given below. Neglect the charge balance.

(i)

Remove all the anions

(X)

, except the central one.

(ii)

Replace all the face centered cations

(M)

, by anions

(X)

(iii)

Remove all the corner cations

(M)

(iv)

Replace the central anion

(X)

, with cation

(M)

.

The value of

(\frac{n u m b e r o f a n i o n s}{n u m b e r o f c a t i o n s})

Z

is _____.

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Science>Chemistry>Structure of The Atom>Valency

The contribution to the total current in a semiconductor, due to electrons and holes are

0.75

and

0.25

respectively. The drift velocity of electrons is

\frac{3}{2}

times that of holes at this temperature. Then the ratio between electron concentration and hole concentration is

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Science>Chemistry>Structure of The Atom>Valency

Among the following, which have highest melting point?

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Science>Chemistry>Structure of The Atom>Valency

An intrinsic semiconductor is converted into

n

-type extrinsic semiconductor by doping it with:-

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Science>Chemistry>Structure of The Atom>Valency

Isotopes of an element contains

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Science>Chemistry>Structure of The Atom>Valency

Define valency.

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Science>Chemistry>Structure of The Atom>Valency

Give one phrase for the following statement:

Process of formation of ions from molecules which are not in the ionic state.

Explain the difference between valence electrons and covalency of an element.

Important Questions on Structure of The Atom

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