Atoms Test

Result

Atoms Test - 62

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

The number of nodal sphere of $$3s-$$orbital are

A
$$1$$

B
$$2$$

C
$$3$$

D
$$0$$

Solution
Question 2
1 / -0

The radius of hydrogen atom, when it is in its second excited state, becomes :

A
half

B
double

C
four times

D
nine times

Solution

The relation between the radius and the orbit of the atom is:
$$r\propto n^2$$

For second excited state, $$n=3$$.
$$r \propto (3)^2$$

$$\Rightarrow r\propto 9$$
Question 3
1 / -0

The order of size of nucleus and Bohr radius of an atom respectively are :

A
$$10^{-14}m, 10^{-10}m$$

B
$$10^{-10}m, 10^{-8}m$$

C
$$10^{-20}m, 10^{-16}m$$

D
$$10^{-8}m, 10^{-6}m$$

Solution
Question 4
1 / -0

A particle moving with a velocity $$\dfrac{1}{10}th$$ of light will cross a nucleus in about:

A
$$10^{-8}sec$$

B
$$10^{-12}sec$$

C
$$10^{-47}sec$$

D
$$10^{-21}sec$$

Solution
Question 5
1 / -0

Stability of half filled sub-shell is caused by :

A
exchange energy

B
greater spin above

C
both $$(a)$$ and $$(b)$$

D
none of the above

Solution
Question 6
1 / -0

Number of lobes of $$2p-$$orbital as in $$yz-$$plane is :

A
$$2$$

B
$$4$$

C
$$6$$

D
$$8$$

Solution
Question 7
1 / -0

The mass of an electron in motion depends upon :

A
direction fotion

B
its velocity

C
initiial mass of $$e^-$$

D
its shell number

Solution
Question 8
1 / -0

In Bohr's radius is $$R_0$$ then radius of $$3^{rd}$$ orbit of hydrogen atom will be :

A
$$3R_0$$

B
$$6R_0$$

C
$$9R_0$$

D
$$12R_0$$

Solution
Question 9
1 / -0

Mark out the incorrect statement:

A
A free neutron can transform itself into photon

B
A free proton can transform itself into neutron

C
In beta minus decay, the electron originates from nucleus

D
All of the above

Solution

When a free neutron decays to a proton along with an electron and an antineutrino, the $$Q$$ value of the reaction is positive which means the reaction is possible all by itself. Hence, statement A is correct.
A free proton cannot convert itself into a neutron due to negative $$Q$$ value. Hence, statement B is incorrect.
In beta minus decay, the electron originates from nucleus only, by the transformation of neutron into a proton, with simultaneous emission of an antineutrino, this reaction is same as the first one and so it is feasible. Hence, statement C is correct.
Question 10
1 / -0

Taking the Bohr radius as $$a_0 = 53 pm$$, the radius of $$Li^{++}$$ ion in its ground state, on the basis of Bohr's model, will be about

A
$$53 pm $$

B
$$27 pm $$

C
$$18 pm $$

D
$$13 pm $$

Solution

According to Bohr's model of atom, radius of an atom in its ground state is $$r = \dfrac{r_o}{z}$$ where $$r_o$$ is Bohr's radius, and Z is atomic number.
As $$r_o = 53 pm$$ and atomic number of Lithium atom is $$3$$ so, $$r = \dfrac{53}{3} = 17.67 pm = 18 pm$$ verifies option (c).