Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

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What is a molecule? Draw a diagram to show the arrangement of molecules in solids and gases.

Important Questions on Develop models to describe the atomic composition of simple molecules and extended structures.

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Among the following, which have highest melting point?

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

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?

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

An intrinsic semiconductor is converted into

n

-type extrinsic semiconductor by doping it with:-

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Silicon doped with gallium forms

MEDIUM

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

An element occurring in the

BCC

structure has

12.05 \times 10^{23}

unit cells. The total number of atoms of the element in these cells will be

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Glass is

MEDIUM

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

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

MEDIUM

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Which of the following oxides shows electrical properties like metals?

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

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

(C a^{2 +})

and fluoride ion

(F^{-})

are

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

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

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Which among the following is NOT a polar molecular solid ?

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

The number of moles in $400 g$ ${CaCO}_{3}$ is _____ moles.

[Hint: Gram atomic masses: $Ca = 40 g, C = 12 g, O = 16 g$ ]

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Match the following

List - I List-II
A) Metallic solid I) Carbon tetrachloride
B) Covalent solid II) Calcium fluoride
C) Molecular solid III) Copper
D) Ionic solid IV) Silicon carbide
V) Glass

The correct answer is

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

In the following circuit diagram, the current through the battery is

Question Image

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

A compound formed by elements

X

and

Y

crystallises in the cubic structure, where

X

atoms are at the corners of a cube and

Y

atoms are at the centre of the body. The formula of the compounds is

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Which of the following is not a conductor of electricity?

MEDIUM

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

The density of an electron-hole pair in pure germanium is

3 \times 10^{16} m^{- 3}

at room temperature. On doping with aluminium, the hole density increases to

4.5 \times 10^{22} m^{- 3}

. Now the electron density (in

m^{- 3}

) in doped germanium will be

MEDIUM

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

The radius of

K^{+}

is

133 pm

and that of

{Cl}^{-}

is

181 pm

. The volume of the unit cell of

KCl

expressed in

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

is:

HARD

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

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).

Question Image

EASY

Physical Sciences>Matter and Its Interactions>Develop models to describe the atomic composition of simple molecules and extended structures.>Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

The majority charge carries in a

N -

type semiconductor are _____.