Classification of Elements and Periodicity in Properties Questions & Answers: NEET UG Chemistry

NEET UG 2025 question paper (official, booklet 45)

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Which of the following statements are true?
A. Unlike Ga that has a very high melting point, Cs has a very low melting point.
B. On Pauling scale, the electronegativity values of N and Cl are not the same.
C. Ar, \(\mathrm{K^+}\), \(\mathrm{Cl^-}\), \(\mathrm{Ca^{2+}}\), and \(\mathrm{S^{2-}}\) are all isoelectronic species.
D. The correct order of the first ionization enthalpies of Na, Mg, Al, and Si is Si > Al > Mg > Na.
E. The atomic radius of Cs is greater than that of Li and Rb.
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Which among the following electronic configurations belong to main group elements?
A. \([\mathrm{Ne}]3s^1\) B. \([\mathrm{Ar}]3d^3 4s^2\) C. \([\mathrm{Kr}]4d^{10}5s^2 5p^5\) D. \([\mathrm{Ar}]3d^{10}4s^1\) E. \([\mathrm{Rn}]5f^0 6d^2 7s^2\)
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Arrange the following elements in increasing order of first ionization enthalpy:
Li, Be, B, C, N
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Which of the following statements are NOT correct?
A. Hydrogen is used to reduce heavy metal oxides to metals.
B. Heavy water is used to study reaction mechanism.
C. Hydrogen is used to make saturated fats from oils.
D. The H-H bond dissociation enthalpy is lowest as compared to a single bond between two atoms of any element.
E. Hydrogen reduces oxides of metals that are more active than iron.
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Which one of the following statements is correct?

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The element expected to form largest ion to achieve the nearest noble gas configuration is :

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Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R :
Assertion A : Metallic sodium dissolves in liquid ammonia giving a deep blue solution, which is paramagnetic.
Reasons R : The deep blue solution is due to the formation of amide.
In the light of the above statements, choose the correct answer from the options given below :

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The IUPAC name of an element with atomic number 119 is

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Match List - I with List - II.
List - I: (a) Li (b) Na (c) KOH (d) Cs
List - II: (i) absorbent for carbon dioxide (ii) electrochemical cells (iii) coolant in fast breeder reactors (iv) photoelectric cell
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Identify the incorrect statement from the following

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Statement I : Acid strength increases in the order given as HF << HCl << HBr << HI.
Statement II : As the size of the elements F, Cl, Br, I increases down the group, the bond strength of HF, HCl, HBr and HI decreases and so the acid strength increases.
In the light of the above statements, choose the correct answer from the options given below.

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From the following pairs of ions which one is not an iso-electronic pair ?

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In which one of the following arrangements the given sequence is not strictly according to the properties indicated against it ?

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Identify the incorrect match.
Name | IUPAC Official Name
(a) Unnilunium | (i) Mendelevium
(b) Unniltrium | (ii) Lawrencium
(c) Unnilhexium | (iii) Seaborgium
(d) Unununnium | (iv) Darmstadtium

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The following metal ion activates many enzymes, participates in the oxidation of glucose to produce ATP and with Na, is responsible for the transmission of nerve signals.

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Match the following :
Oxide | Nature
(a) CO (i) Basic
(b) BaO (ii) Neutral
(c) Al\(_2\)O\(_3\) (iii) Acidic
(d) Cl\(_2\)O\(_7\) (iv) Amphoteric
Which of the following is correct option ?

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Enzymes that utilize ATP in phosphate transfer require an alkaline earth metal (M) as the cofactor. M is :

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For the second period elements the correct increasing order of first ionisation enthalpy is :

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Which of the following is an amphoteric hydroxide ?

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The method used to remove temporary hardness of water is :

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The correct order of atomic radii in group 13 elements is

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Which of the following oxides is most acidic in nature ?

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The element Z = 114 has been discovered recently. It will belong to which of the following family/group and electronic configuration ?

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In which of the following options the order of arrangement does not agree with the variation of property indicated against it ?

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Which of the following statements is false ?

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Which of the following statements about hydrogen is incorrect ?

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The suspension of slaked lime in water is known as

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