MCQ Questions for Class 11 Medical Chemistry Structure Of Atom Quiz 6

Elements are characterized by the ______ of their atoms.

0%
electrons
0%
mass
0%
protons
0%
shape

The mass number of nucleus is :

0%
Sometimes equal to its atomic number
0%
Sometimes less than and sometimes more than its atomic number
0%
Always less than its atomic number
0%
Always more than its atomic number

Explanation

Mass number of an element is the total number of protons and neutrons present inside the atomic nucleus of the element. It is represented by A. A is different for different elements. Mass number of a nucleus is sometimes equal to its atomic number, for example in case of hydrogen, number of neutrons

$= 0$ .
So, mass number

$=$ atomic number.

Which of the following is not an example of matter?

0%
Chair
0%
Air
0%
Almonds
0%
Touch

How can an element be defined as consisting of any mixture of atoms with a given atomic number?

0%
Determines the mass of of element in the mixture
0%
Determines the chemical properties of an element
0%
Both A and B
0%
None of the above

In Thomson's model, _________ are embedded in a positively charged 'soup'.

0%
electrons
0%
neutrons
0%
protons
0%
ions

Which of the following disproved Thomson's model?

0%
The nuclear model of an atom
0%
The electron model of an atom
0%
The atomic model of an atom
0%
None of above

____________ is an obsolete scientific model of the atom proposed by J. J. Thomson in

$1904$ .

0%
Musk melon model
0%
Plum pudding model
0%
Christmas melon model
0%
Pudding model

On the basis of composition, which of the following is a type of matter?

0%
Compound
0%
Solid
0%
Liquid
0%
Both b and c

Thomson's atomic model is also called :

0%
water melon model
0%
christmas pudding model
0%
both a and b
0%
none of above

How many orbitals are there in the second principal energy level, n = 2, of an atom?

0%
$1$
0%
$9$
0%
$4$
0%
$16$

Explanation

There are four orbitals in the second principal energy level, n = 2, of an atom. These include one 2s orbital and three 2p orbitals. Three 2p orbitals include

$2p_x$ ,

$2p_y$ and

$2p_z$ orbitals.

Which sublevel can occupy a maximum of 10 electrons?

0%
s
0%
f
0%
p
0%
d

The electronic configuration

$\displaystyle { 1s }^{ 2 },{ 2s }^{ 2 },{ 2p }^{ 6 },{ 3s }^{ 2 },{ 3p }^{ 6 },{ 3d }^{ 9 }$ represents a:

0%
metal atom
0%
non-metal atom
0%
non-metallic anion
0%
metallic cation

J.J. Thomson received noble prize in the year:

0%
$1900$
0%
$1906$
0%
$1909$
0%
$1920$

Explanation

J.J. Thomson received noble prize in the year

$1906$ for his work on electrical conductivity of gases.

Radioactive changes and ordinary chemical changes are different, because radioactive changes:

0%
are explosive
0%
gain energy
0%
happens in the nucleus
0%
release energy

Bohr's atom model assumes.

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The nucleus is of infinite mass and is at rest
0%
Electrons in a quantized orbit will not radiate energy
0%
Mass of electron remains constant
0%
All the above.

Which one contains up to ten electrons from the following?

0%
$1s$
0%
$2s$
0%
$3s$
0%
$3p$
0%
$3d$

Which of the following can occupy space and has mass?

0%
Density
0%
Weight
0%
Matter
0%
A solid
0%
Volume

Which of the following cannot be accelerated?

0%
$\alpha$ -particle
0%
$\beta$ -particle
0%
Protons
0%
Neutrons

Explanation

Neutrons cannot be accelerated as they are chargless (neutral) particles. Protons,

$\displaystyle \alpha -$ particles and

$\displaystyle \beta -$ particles can be accelerated as they are charged particles.

Which of the following contains up to

$10$ electrons.

0%
$1s$
0%
$2s$
0%
$3s$
0%
$3p$
0%
$3d$

Thomson's atomic model suggested that the atom is:

0%
not divisible
0%
divisible
0%
electrons revolve around nucleus
0%
both A and C

Isotopes have same :

0%
atomic mass
0%
atomic number
0%
atomic radius
0%
electronegativity
0%
ionization potential

X is defined by the number of protons. What is X?

0%
Cation
0%
Inert Gas
0%
Crystal
0%
Anion
0%
Element

Which element has a mass number of 20 and contains 11 neutrons?

0%
Copper
0%
Gallium
0%
Calcium
0%
Sodium
0%
Fluorine

Explanation

Mass number (A) = Number of protons + Number of neutron

$\therefore$ Number of proton = Mass number - Number of neutron

$\therefore$ Number of proton =

$20-11=9$

So, here the number of protons is 9.

Fluorine contains 9 protons.

Thus, option D is correct.

What happens when both of the orbitals in a molecule are in phase, either both positive or both negative and the electrons in the bonds are at their lowest energy level?

0%
Bonding takes place.
0%
The chemicals don't react.
0%
The atoms don't bond.
0%
Bonding doesn't take place.
0%
The electrons in the atoms don't share orbitals.

Which statement below is not acceptable with the concept of isotopes?

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Each elements is composed of atoms
0%
All atoms of an element are identical
0%
The atoms of different elements have different chemical and physical properties
0%
The combining of elements leads to the formation of compounds
0%
In a compound, the kinds and numbers of atoms are constant

Who postulated that electrons revolve in orbits around the nucleus?

0%
Bohr model
0%
deBroglie's wave hypothesis
0%
Heisenberg's uncertainty principle
0%
Dalton
0%
Rutherford

If Atom

$1$ has 19 protons and 22 neutrons and Atom

$2$ has 20 protons and 22 neutrons, are these isotopes of the same element?

0%
There is not enough information to determine this.
0%
No, because they have different numbers of protons.
0%
No, because they have the same number of neutrons.
0%
Yes, because they have different numbers of protons.
0%
Yes, because they have the same number of neutrons.

Explanation

If Atom

$1$ has 19 protons and 22 neutrons and atom

$2$ has 20 protons and 22 neutrons, these are not isotopes of the same element. Because they have different numbers of protons. Isotopes have same number of protons but different number of neutrons.

According to Bohr's model of the atom, atoms emit or absorb radiation only at certain wavelengths.Identify why is it so

0%
Because the protons and electrons are distributed evenly throughout the atom
0%
Because electrons can orbit the nucleus at any radius
0%
Because electrons orbit the nucleus only at certain discrete radii
0%
Because protons orbit the nucleus only at certain discrete radii
0%
Because photons can only have discrete wavelength

Explanation

Bohr's frequency condition is given by

$hc/\lambda=E_{2}-E_{1}$

Above relation shows that wavelength

$\lambda$ of radiation depends upon energy difference of two orbits,

$\lambda$ is certain because energy difference is constant for two orbits it means

$E_{1}$ and

$E_{2}$ are also fixed i.e. electron is revolving in some fixed orbits of discrete radii. These orbits are called stationary orbits in which electron does not emit energy when revolving in these orbits.

Maximum number of electrons held in the d orbitals is :

0%
$2$
0%
$6$
0%
$8$
0%
$10$
0%
$14$

Which of the following assumptions made by Neils Bohr regarding the hydrogen atom was NOT new and "radical"?

0%
Electrons are only stable in certain orbits
0%
Atoms only emit electromagnetic radiation when electrons transition to lower energy states
0%
The Coulomb force is responsible for keeping the electron in orbit around the positive nucleus
0%
An electron in a hydrogen atom can only orbit the nucleus if its angular momentum is some integer multiple of $h/2 \pi$
0%
All of the above were new and "radical"

According to J.J Thomson's atomic model, negative charges are embedded in:

0%
A lump of positive charge
0%
A lump of neutral particles
0%
A lump of small atoms
0%
The nucleus

An atom with atomic number

$20$ is most likely to combine chemically with the atom whose atomic number is___________.

0%
$11$
0%
$16$
0%
$18$
0%
$10$

Explanation

Atomic number

$20$ will be distributed in electron shell as

$2,8,8,2$ .

Its valency is

$2$ . It will loose this

$2$ electron to gain stability and noble gas configuration. If atomic number

$11$ is distributed in electron shell it will be

$2,8,1$ .

Atom with valence electron

$1$ will loose this atom to gain stability. Hence, both

$_{20}X$ &

$_{11}X$ will gain nothing i.e. will not gain stable electronic configuration after combining with each other.

An atom with atomic number

$16$ has electronic configuration as

$2,8,6$ .It will gain

$2$ electron from

$_{20}X$ and complete its octet. Thus atom having atomic number

$20$ will combine most likely with atom having atomic number

$16$ as both will gain stable electronic configuration.

An electron jumps from 3rd orbit to 2nd orbit by gaining the difference of energy of the two levels.

0%
True
0%
False

Every matter can be seen.

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True
0%
False

The value of first Bohr's radius of a hydrogen atom is ________.

0%
$0.529A^o$
0%
$5.29 \times 10^{-12}$
0%
$5.29A^o$
0%
none of these

Explanation

The radius of

$n^{+n}$ Bohr orbit is given by,

$r_n=\dfrac { { n }^{ 2 }{ n }^{ 2 } }{ 4{ \pi }^{ 2 }{ mZe }^{ 2 } }$

Now, for hydrogen, Ze=1 and

for first orbit, n=1

$\therefore r_1=\dfrac { { n }^{ 2 } }{ 4{ \pi }^{ 2 }{ me }^{ 2 } } =0.529°$

Thus, Bohr radius is the mean radius of the orbit of an electron around the nucleus of a hydrogen atom at its ground state.

The change in velocity when electron jumps from the first orbit to the second orbit is__________.

0%
half of its original velocity
0%
twice of its original velocity
0%
one fourth of its original velocity
0%
equal to its original velocity

Explanation

Total Energy of electron,

$E_T =$ Potential energy (PE) + Kinetic energy (KE)

For an electron revolving in a circular orbit of radius, r around a nucleus of H atom:

$PE = -Ze^2/r$

and

$KE = Ze^2/2r$

Thus ,

$E_T = (-Ze^2/r) + (Ze^2/2r) = -Ze^2/2r=-KE$

For hyrogen atom:

$E_T=E_n=-R_H(1/n^2)$

For n=1,

$E_1=-R_H$ and

$KE_1=\frac{1}{2}mv_1^2$

For n=2,

$E_2=-R_H/4$ and

$KE_2=\frac{1}{2}mv_2^2$

Since

$E_n =-KE$

thus,

$\dfrac {E_1}{E_2}=\dfrac {KE_1}{KE_2}$

$\dfrac {1}{1/4}=\dfrac {v_1^2}{v_2^2}$

$v_2^2=v_1^2/4$

$v_2=v_1/2$

velocity in second orbit is half of the velocity in first orbit.

option A is correct

An element has an atomic number

$20$ . How many electrons will be present in

$K, L, M$ and

$N$ shells of its atom?

0%
$2, 8, 6, 4$
0%
$2, 8, 7, 3$
0%
$3, 7, 7, 3$
0%
$2, 8, 8, 2$

Explanation

Calcium with atomic number

$20$ will have

$2, 8, 8, 2$ electrons in

$K, L, M$ and

$N$ shells respectively.

$K, L, M$ shells can accomodate

$2, 8, 8$ electrons respectively. The remaining 2 electrons will enter

$N$ shell.

An element has atomic number

$17$ and mass number

$37$ . There are

$17$ electrons outside the nucleus. Find the number of neutrons in it.

0%
$20$
0%
$21$
0%
$17$
0%
$37$

Explanation

$(A)$

$20$

$Given$ - Atomic number of element =

$17$

Mass number of element =

$37$

Number of electrons =

$17$

As we know, number of protons is equal to number of electrons.

so, number of protons =

$17$

now,

$Mass\ number$ =

$number\ of\ protons$ +

$number\ of\ neutrons$

$37$ =

$17$ + number of neutrons

number of neutrons =

$37$ -

$17$

number of neutrons =

$20$

So, the number of neutrons in the nucleus =

$20$ .

The atom of an element has

$10$ electrons,

$10$ protons and

$12$ neutrons. Find the mass number of the element:

0%
$10$
0%
$12$
0%
$22$
0%
$32$

Explanation

The total number of protons and neutrons in the nucleus is called mass number of the atom. It is generally represented by th letter

$A$ .

$Mass$

$Number(A)$ =

$Number\ of\ Protons$ +

$Number\ of\ Neutrons$

As given, the atom of an element contains

$10$ protons and

$12$ neutrons , therefore,

$mass$

$number$ =

$10$ +

$12$ =

$22$

So, the mass number of the element is 22.

Multiple Answer Question
In Bohr's model of the atom:

0%
electrons revolve around the nucleus in circular orbits
0%
these circular orbits or shells are stationary
0%
each shell in associated with a definite amount of energy
0%
all shells have equal energy level

What does Bohr's atomic theory explain?

0%
About quantum numbers
0%
About the shape of sub-levels
0%
About nucleus
0%
About stationary states

Explanation

The Bohr's atomic theory explains about the presence of stable orbits or stationary states. This theory thus was able to overcome drawback of Rutherford's theory. Thus the correct option is

$\text{D}$ .

An atom has mass number

$23$ and atomic number

$11$ . How many protons, electrons and neutrons are present in the atom?

0%
$11, 12, 13$
0%
$11, 11, 12$
0%
$11, 11, 13$
0%
$11, 14, 15$

Explanation

$(B)$

$11,11,12$

$Given$ - Mass number of atom =

$23$

Atomic number of atom =

$11$

As, no. of electrons in an atom is equal to an atomic number of the element.

So, number of electrons =

$11$

Secondly , number of protons are equal to number of electrons.

so, number of protons =

$11$

And number of neutrons = mass number - atomic number =

$23 - 11$ =

$12$

so, number of neutrons =

$12$

So , the atom contains

$11 \ protons$ ,

$11 \ electrons$ ,

$12\ neutrons$ .

A, B, C are three elements with atomic numbers, Z-1, Z, and Z+1 respectively. B is an inert gas.

Identify the group to which A and C belong.

0%
Alkali metal, Alkaline earth metal
0%
Halogen, Alkali metal
0%
Inert gas, Alkali metal
0%
Halogens, Inert gas

The number of nucleons in the isotope of an atom

$_ZX^m$ are _________.

0%
m
0%
Z
0%
m + Z
0%
m - Z

Explanation

Mass number (

$m$ )

$=$ number of proton

$+$ neutrons

$=$ number of nucleons.

The mass number (atomic weight) also called atomic mass number or nucleon number is the total number of protons and neutrons (together known as nucleons) is an atomic nucleus. It determines the atomic mass of atoms.

How would fingerprints on a cuvette during a visible spectrometry lab affect the concentration reading?

0%
Concentration would be lower, since more light is being reflected and not detected by the spectrometry light sensor.
0%
Concentration would be higher since more light is being reflected or absorbed, increasing the absorbance reading.
0%
Concentration will stay the same since the fingerprints will only deflect the light slightly and not enough to affect the absorbance measurements.
0%
Concentration will be increase since more light is absorbed by the solution, resulting in a decrease in the absorbance measurement.

The atomic number (Z) of an element isIn its ground state, how many electrons are present in the N shell:

0%
13
0%
2
0%
15
0%
3

Explanation

Atomic number = 25. The element is Mn.

The electronic configuration of Mn is

$1s^22s^22p^63s^23p^64s^23d^5$ .

N- shell is 4th shell.

$\therefore$ n = 4

The number of electrons present in n = 4 is 2.

$\textbf{Additional information}$

For K - shell

$\rightarrow$ n = 1

For L - shell

$\rightarrow$ n = 2

For M- shell

$\rightarrow$ n = 3

How are the two atoms

$_{ 92 }^{ 235 }{ P }$ and

$_{ 92 }^{ 238 }{ P }$ similar?
(i) They have the same number of protons
(ii) They have the same number of neutrons
(iii) They have the same number of electrons

0%
Only (i)
0%
Only (i) and (ii)
0%
Only (i) and (iii)
0%
(i), (ii) and (iii)

Explanation

$_{Z}^{A}{X}$ : Ideal element representation

Here,

$Z=$ atomic number

$=$ number of protons

$A$

$=$ mass number

$=$ number of protons

$+$ number of neutrons

Also, the number of protons

$=$ number of electrons

So, for

$_{92}^{235}{P}$ and

$_{92}^{238}{P}$ :

$_{92}^{235}{P}$ : number of protons

$=$

$92$

$=$

$Z$

Number of electrons

$=$

$92$

$=$ number of protons

Number of neutrons

$=$

$A-Z$

$=$

$235-92$

$=$

$143$

$_{92}^{238}{P}$ : number of protons

$=$

$Z$

$=$

$92$

Number of electrons

$=$ number of protons

$=$

$Z$

$=$

$92$

Number of neutrons

$=$

$238-92$

$=$

$146$

Multiple Answer Question.
From Bohr's model radius of the orbit and energy of the hydrogen atom are calculated as :

0%
Radius of the 1st orbit is $0.529 ^oA$
0%
Energy of the 1st orbit is $-13.6 \ eV$
0%
Energy of the 1st orbit is $-21.72 \times 10^{-19}J$
0%
Radius of the 1st orbit is $1.06 ^oA$

Explanation

From Bohr's model of single elctron species,

$r=0.529\dfrac{n^2}{Z}A^0,E=-13.6\dfrac{Z^2}{n^2}eV$

For

$H$ atom,

$r=0.529A^0, E=-13.6eV=-13.6\times1.6\times10^{-19} J$

Which of the following statement in relation to the calcium atom is incorrect?

0%
$3s$ orbital is lower in energy than $3p$ orbital
0%
$3p$ orbital is lower in energy than $3d$ orbital
0%
$3s, 3p$ and $3d$ orbitals all have the same energy
0%
$3s, 3p$ and $3d$ orbitals do not have the same energy

Explanation

$3s,3p,3d$ orbitals don't have same energy.

According to

$(n+l)$ rule, Order of energy of subshells:

$3s<3p<3d$

The spectral lines remain unaltered under the presence of external magnetic or electric field.

0%
True
0%
False

CBSE Questions for Class 11 Medical Chemistry Structure Of Atom Quiz 6 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

CBSE Questions for Class 11 Medical Chemistry Structure Of Atom Quiz 6 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

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