You visited us 23 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Chemistry

Thomson's Discovery of Electrons

Assertion :Sh...

Question

Assertion :Shielding effect increases as we go down the group. Reason: More is the number of electrons in the penultimate shell, more is the shielding.

Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Assertion is correct but Reason is incorrect

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Both Assertion and Reason are incorrect

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
Complete electron shells shield the nuclear charge very effectively. On moving down the group, the number of complete electron shells increases. Also, the nuclear core is farther removed from the valence electrons.

Suggest Corrections

Similar questions

Q. Assertion : Two electrons of helium atom are placed in only one shell but three electrons of lithium need two shells.
Reason: A shell can have maximum

{2n}^{2}

electrons.

Q. Read the assertion and reason carefully to mark the correct option out of the options given below:

(a)If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b)If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c)If assertion is true but reason is false.

(d)If assertion is false but reason is true.
Assertion: Ionisation enthalpies for early actinoids are lower than that for early lanthanoids.
Reason: 5f electrons more effectively shielded from the nuclear charge than the 4f electrons
of the corresponding lanthanoids.

Q. Assertion: The compressibility factor for

H_{2}

and

H e

(1 + \frac{P b}{R T})

Reason: The compressibility factor for

H_{2}

and

H e

can be derived from Van der Waal's equation.

In the following question a statement of assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below in each question.
Assertion (A) Electron gain enthalpy becomes less negative as we go down a group.
Reason. (R) size fo the atom inscreses on going down the group and the added electron would be farther from the nucleus.
(a) Assertion and reason both are correct statement but reason is not correct explanation for assertion.
(b) assertion and reason both are correct statements and reason is correct explanation for assertion .
(c) Assertion and reason both are wrong statements.
(d) Assertion is wrong statement but reason is correct statement.

Q. Assertion: The impurities such as

{SiO}_{2}

present in iron ore is removed by

{CaCO}_{3}

.

Reason:

CaO

formed by decomposition of

{CaCO}_{3}

reacts with

{SiO}_{2}

to form slag.

Join BYJU'S Learning Program