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Periodic Table & Periodicity

NEET Chemistry · 94 questions · Page 2 of 10 · Click an option or "Show Solution" to reveal answer

Q11
Gadolinium has a low value of third ionisation enthalpy because of
A small size
B high exchange enthalpy
C high electronegativity
D high basic character
Correct Answer
Option B
Solution

Electronic configuration of Gadolinium Gd :- [Xe] 4f 7 5d 1 6s 2 In case of 3 rd ionisation enthalpy electron will be removed from 5d and resultant configuration will be [Xe]4f 7 that is stable electronic configuration as it will have high exchange energy, hence less energy will be required to remove 3 rd electron.

Q12

Identify the incorrect match.<br><table> <thead> <tr> <th>Name</th> <th></th> <th></th> <th>IUPAC Official Name</th> </tr> </thead> <tbody> <tr> <td>

List - IList - II
(A) </td> <td>Unnilunium</td> <td> (i) </td> <td>Mendelevium</td> </tr> <tr> <td>
(B) </td> <td>Unniltrium</td> <td> (ii) </td> <td>Lawrencium</td> </tr> <tr> <td>
(C) </td> <td>Unnilhexium</td> <td> (iii) </td> <td>Seaborgium</td> </tr> <tr> <td>
(D) </td> <td>Unununnium</td> <td> (iv) </td> <td>Darmstadtium</td> </tr> </tbody> </table>
A (B), (ii)
B (C), (iii)
C (D), (iv)
D (A), (i)
Correct Answer
Option C
Solution

Unununnium Atomic number = 111 IUPAC official name : Roentgenium (Rg) not Darmstadtium.

Q13

Match the following : <br><table> <thead> <tr> <th>Oxide</th> <th></th> <th></th> <th>Nature</th> </tr> </thead> <tbody> <tr> <td>

List - IList - II
(A) </td> <td>CO</td> <td> (i) </td> <td>Basic</td> </tr> <tr> <td>
(B) </td> <td>BaO</td> <td> (ii) </td> <td>Neutral</td> </tr> <tr> <td>
(C) </td> <td>Al<sub>2</sub>O<sub>3</sub></td> <td> (iii) </td> <td>Acidic</td> </tr> <tr> <td>
(D) </td> <td>Cl<sub>2</sub>O<sub>7</sub></td> <td> (iv) </td> <td>Amphoteric</td> </tr> </tbody> </table><br>Which of the following is correct option?
A <table> <thead> <tr> <th>(A)</th> <th>(B)</th> <th>(C)</th> <th>(D)</th> </tr> </thead> <tbody> <tr> <td>(ii)</td> <td>(i)</td> <td>(iv)</td> <td>(iii)</td> </tr> </tbody> </table>
B <table> <thead> <tr> <th>(A)</th> <th>(B)</th> <th>(C)</th> <th>(D)</th> </tr> </thead> <tbody> <tr> <td>(iii)</td> <td>(iv)</td> <td>(i)</td> <td>(ii)</td> </tr> </tbody> </table>
C <table> <thead> <tr> <th>(A)</th> <th>(B)</th> <th>(C)</th> <th>(D)</th> </tr> </thead> <tbody> <tr> <td>(iv)</td> <td>(iii)</td> <td>(ii)</td> <td>(i)</td> </tr> </tbody> </table>
D <table> <thead> <tr> <th>(A)</th> <th>(B)</th> <th>(C)</th> <th>(D)</th> </tr> </thead> <tbody> <tr> <td>(i)</td> <td>(ii)</td> <td>(iii)</td> <td>(iv)</td> </tr> </tbody> </table>
Correct Answer
Option A
Solution

CO : Neutral oxide BaO : Basic oxide Al 2 O 3 : Amphoteric oxide Cl 2 O 7 : Acidic oxide

Q14
For the second period elements the correct increasing order of first ionization enthalpy is :
A Li < B < Be < C < N < O < F < Ne
B Li < Be < B < C < O < N < F < Ne
C Li < B < Be < C < O < N < F < Ne
D Li < Be < B < C < N < O < F < Ne
Correct Answer
Option C
Solution

Ionisation enthalpy increases in a period from left to right, because of increased nuclear charge and decrease in atomic radii.

But because of half filled orbitals of Be, N and fully filled orbitals of Ne, stability of those atoms inceases.

So, the correct increasing order of first ionisation enthalpy will be : Li < B < Be < C < O < N < F < Ne

Q15
The correct order of atomic radii in group 13 elements is
A B < Al < In < Ga < Tl
B B < Al < Ga < In < Tl
C B < Ga < Al < Tl < In
D B < Ga < Al < In < Tl
Correct Answer
Option D
Solution

Ga is slightly smaller than Al due poor shielding of d e – so Z eff increasing. So, Atomic size : B < Ga < Al < In < Tl

Q16
Which of the following oxides is most acidic in nature?
A MgO
B BeO
C BaO
D CaO
Correct Answer
Option B
Solution

In metals, on moving down the group, metallic character increases, so basic nature increases hence most acidic will be BeO.

In fact, BeO is amphoteric oxide while other given oxides are basic oxides.

Q17
The element Z = 114 has been discovered recently. It will belong to which of the following family/group and electronic configuration ?
A Carbon family, [Rn] 5f 14 6d 10 7s 2 7p 2
B Oxygen family, [Rn] 5f 14 6d 10 7s 2 7p 4
C Nitrogen family, [Rn] 5f 14 6d 10 7s 2 7p 6
D Halogen family, [Rn] 5f 14 6d 10 7s 2 7p 5
Correct Answer
Option A
Solution

The electronic configuration of th element with Z = 114 is [Rn] 5f 14 6d 10 7s 2 7p 2 .

Hence it belongs to the carbon family which has the same outer electronic configuaration.

Q18
The species Ar, K + and Ca 2+ contain the same number of electrons. In which order do their radii increase ?
A Ca 2+ < K + < Ar
B K + < Ar < Ca 2+
C Ar < K + < Ca 2+
D Ca 2+ < Ar < K +
Correct Answer
Option A
Solution

For isoelectronic species, radius of atom decreases with increase in nuclear charge.

Q19
Which of the following orders of ionic radii is correctly represented ?
A H −- > H∙^ \bullet > H +
B Na + > F −- > O 2−-
C F −- > O 2−- > Na +
D All 3+ > Mg 2+ > N 3−-
Correct Answer
Option A
Solution

Cation loose electrons are smaller in size than the parent atom, where anions gain electrons are larger in size than the parent atom.

Hence the order is H - > H > H +

Q20
Which one of the following arrangements represents the correct order of least negative to most negative electron gain enthalpy for C, Ca, Al, F and O?
A All < Ca < O < C < F
B All < O < C < Ca < F
C C < F < O < All < Ca
D Ca < All < C < O < F
Correct Answer
Option D
Solution

Electron gain enthalpy becomes less negative from top to bottom in a group while it becomes more negative from left to right within a period.

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