Structure of Atom Test

Result

Structure of Atom Test - 58

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Mass numbers of Li, Be and B are 7, 9 and 10 respectively. Which of the following has two electrons, three protons and four neutrons?

A
$$Be^+$$

B
$$Be^{2+}$$

C
$$Li^+$$

D
$$B$$

Solution

Explanation :
As $$Li$$ has $$3$$ electron. So, $$Li^+$$, would have $$2$$ electrons only.

As atomic number of $$Li$$ is $$3$$ so number of proton will be $$3$$ and

number of the neutron = mass number - number of proton.

Therefore, $$7-3=4$$, so it would have $$4$$ neutron.

The correct option is (C).
Question 2
1 / -0

The ratio of the energy of the electron in the ground state of hydrogen to the electron in first excited state of $$Be^{3+}$$ is

A
$$1 : 4$$

B
$$1 : 8$$

C
$$1 : 16$$

D
$$16 : 1$$

Solution

Formula,

$$E=E_0 \dfrac{z^2}{n^2}$$

hydrogen,

$$E=E_0 \dfrac{z^2}{n^2}=E_0 \dfrac{1^2}{1^2}$$

$$E=E_0$$

$$Be^{3+},$$

$$E=E_0 \dfrac{z^2}{n^2}=E_0 \dfrac{4^2}{2^2}$$

$$E=4E_0$$

$$Ratio=\dfrac{E_0}{4E_0}$$

$$1:4$$
'
Question 3
1 / -0

The Bohr radius of the fifth electron of phosphorus (atomic number = 15) acting as dopant in silicon (relative dielectric constant = 12) is

A
10.6$$\ { A^0 }$$

B
0.53$$\ { { A ^0} }$$

C
21.2$$ { A^0 }$$

D
None of these

Solution

$${r_n} = { \in _r}\left( {\frac{{{n^2}}}{Z}} \right)$$
$${a_0} = 12 \times \frac{{{{\left( 5 \right)}^2}}}{{15}} \times 0.53 = 10.6\mathop A\limits^0 $$
Hence,
option $$(A)$$ is correct answer.
Question 4
1 / -0

According to Bohr's theory radius of $$n^{th}$$ shell is given as $$\dfrac {1}{r_{n}}\propto Z^{y}$$ ($$Z$$ is atomic number). Here $$'y'$$ is:

A
$$-1$$

B
$$1$$

C
$$2$$

D
$$-2$$

Solution

According to Bohr's theory radius of any shell $$r_{n}$$ is proportional to $$\dfrac{n^{2}}{Z}$$ where n= principle quantum no and Z = atomic number.

So, $$1/r_{n}$$ is proportional to $$\dfrac{Z}{n^{2}}$$ .

So the correct option is B.
Question 5
1 / -0

The radius of the orbit of an electron in a Hydrogen-like atom is $$3{ a }_{ 0 }$$, where $${ a }_{ 0 }$$ is the Bohr radius. Its orbital angular momentum is $$\frac { 3h }{ 2\pi } $$. It is given that h is Planck's constant and R is Rydberg constant. The possible wavelength, when the atom de-excites is :

A
$$\dfrac { 4 }{ 5R } $$

B
$$\dfrac { 4 }{ 9R } $$

C
$$\dfrac { 1 }{ 2R } $$

D
$$\dfrac { 9 }{ 32R } $$

Solution

solution:
given ;
$$4.5a_0 = a_0 \dfrac{n^2}{Z}----(i)$$
$$\dfrac{nh}{2\pi} = \dfrac{3h}{2\pi} ----(ii)$$

so , n= 3 and z=2
so , possible wavelength are:

$$\dfrac{1}{\lambda _1}= RZ^2[\dfrac{1}{1^2} - \dfrac{1}{3^2}] \Rightarrow \lambda _1= \dfrac{9}{32R}$$

hence the correct option:D
Question 6
1 / -0

$$M^{3+}$$ (mass number $$56$$) contains $$30.4\%$$ more neutrons than electrons. Thus, atomic number of the ion is.

A
$$23$$

B
$$24$$

C
$$25$$

D
$$26$$

Solution
Question 7
1 / -0

Which one of the following is considered as the main postulate of Bohr's model of atom

A
Protons are present in the nucleus

B
Electrons are revolving around the nucleus

C
Centrifugal force produced due to the revolving electrons balances the force of attraction between electron and protons

D
Angular momentum of electron is an integral multiple of $$\dfrac{h}{2\pi}$$

Solution
Question 8
1 / -0

Any $$nf-$$ orbital can accommodate upto:-

A
$$14$$ electron

B
Six electrons

C
Two electrons with parallel spin

D
Two electrons with opposite spin

Solution
Question 9
1 / -0

Which one of the following species will give a series of spectral lines similar to that of $$Mg^{2+}$$?

A
$$Al^{3+}$$

B
$$Na$$

C
$$Mg^+$$

D
$$F$$

Solution

option 1 should be correct
because Mg2+ and Al3+ have same no. of electron in their orbitats ( that is 10)
Question 10
1 / -0

If the Aufbau principle had not been followed, $$Ca(Z=20)$$ would have been placed in the?

A
s-block

B
p-block

C
d-block

D
f-block

Solution

Electronic configuration of Ca is $$1s^22s^22p^63s^23p^64s^2$$.
Filling of 3d orbital starts after the filling of 4s orbitals. If the Aufbau principle had not been followed, the filling of 3d orbital would have been prior to filling of 4s orbital and the electronic configuration of Ca would have been $$1s^22s^22p^63s^23p^63d^2$$ and it would have been placed in the d-block. Hence, correct answer is C.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Structure of Atom Test - 58

Result

Structure of Atom Test - 58

Score

-

Rank

-

SHARING IS CARING

Question 1

$$Be^+$$

$$Be^{2+}$$

$$Li^+$$

$$B$$

Solution

Question 2

$$1 : 4$$

$$1 : 8$$

$$1 : 16$$

$$16 : 1$$

Solution

Question 3

10.6$$\ { A^0 }$$

0.53$$\ { { A ^0} }$$

21.2$$ { A^0 }$$

None of these

Solution

Question 4

$$-1$$

$$1$$

$$2$$

$$-2$$

Solution

Question 5

$$\dfrac { 4 }{ 5R } $$

$$\dfrac { 4 }{ 9R } $$

$$\dfrac { 1 }{ 2R } $$

$$\dfrac { 9 }{ 32R } $$

Solution

Question 6

$$23$$

$$24$$

$$25$$

$$26$$

Solution

Question 7

Protons are present in the nucleus

Electrons are revolving around the nucleus

Centrifugal force produced due to the revolving electrons balances the force of attraction between electron and protons

Angular momentum of electron is an integral multiple of $$\dfrac{h}{2\pi}$$

Solution

Question 8

$$14$$ electron

Six electrons

Two electrons with parallel spin

Two electrons with opposite spin

Solution

Question 9

$$Al^{3+}$$

$$Na$$

$$Mg^+$$

$$F$$

Solution

Question 10

s-block

p-block

d-block

f-block

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.