Electronic configuration of four elements A, B, C and D are given below : (A) 1mathrms^2 2mathrms^2 2mathrmp^3 (B) 1mathrms^2 2mathrms^2 2mathrmp^4 (C) 1mathrms^2 2mathrms^2 2mathrmp^5 (D) 1mathrms^2 2mathrms^2 2mathrmp^2 Which of the following is the correct order of increasing electronegativity (Pauling's scale)?

Solution & Explanation

### Related Formula chi_mathrmP propto Z_texteff propto frac1textAtomic Radius quad text(Across a period) ### Core Logic Let's first identify each element based on its electronic configuration: (A): 1mathrms^2 2mathrms^2 2mathrmp^3 implies textAtomic Number 7 implies textNitrogen (N)

(B): 1mathrms^2 2mathrms^2 2mathrmp^4 implies textAtomic Number 8 implies textOxygen (O)

(C): 1mathrms^2 2mathrms^2 2mathrmp^5 implies textAtomic Number 9 implies textFluorine (F)

(D): 1mathrms^2 2mathrms^2 2mathrmp^2 implies textAtomic Number 6 implies textCarbon (C) ### Step 1: Check Periodic Table Trends All four elements belong to the 2nd period. Electronegativity increases across a period from left to right because nuclear charge (Z_texteff) increases, and atomic radius decreases: textCarbon (D) < textNitrogen (A) < textOxygen (B) < textFluorine (C) On Pauling's scale, the precise values are: - Carbon (D) = 2.55 - Nitrogen (A) = 3.04 - Oxygen (B) = 3.44 - Fluorine (C) = 3.98 ### Step 2: Conclusion The correct increasing order is mathrmD < A < B < C. ### Pattern Recognition Fluorine is the most electronegative element in the entire periodic table (Pauling electronegativity of 4.0). Electronegativity always increases towards the top-right of the main-group elements. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity in Properties

More Classification of Elements and Periodicity in Properties Previous-Year Questions — Page 4

Q jee_main_2025_29_jan_morning Periodic Trends in Properties
An element 'E' has the ionisation enthalpy value of 374 \, mathrmkJ \, mol^-1 . 'E' reacts with elements A, B, C and D with electron gain enthalpy values of -328 , -349 , -325 and -295 \, mathrmkJ \, mol^-1 , respectively. The correct order of the products EA, EB, EC and ED in terms of ionic character is :
  • A. mathrmEB > mathrmEA > mathrmEC > mathrmED
  • B. mathrmED > mathrmEC > mathrmEA > mathrmEB
  • C. mathrmEA > mathrmEB > mathrmEC > mathrmED
  • D. mathrmED > mathrmEC > mathrmEB > mathrmEA

Solution

### Related Formula textIonic Character propto lvert Delta H_textIE - Delta H_textEGE rvert ### Core Logic The relative ionic quality of a standard binary bond rises as the gap scale between ionization enthalpy and negative electron gain enthalpy parameters widens. Comparing the values: * For B: Delta H_textEGE = -349 mathrm~kJ/mol (largest energy release) rightarrow Highest ionic character. * For A: Delta H_textEGE = -328 mathrm~kJ/mol. * For C: Delta H_textEGE = -325 mathrm~kJ/mol. * For D: Delta H_textEGE = -295 mathrm~kJ/mol (smallest energy release) rightarrow Lowest ionic character. Arranging them in descending order of ionic character yields: mathrmEB gt mathrmEA gt mathrmEC gt mathrmED ### Pattern Recognition A highly exothermic electron gain enthalpy value favors easier anion production, widening electronegativity variations to enhance ionic bond properties. ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity in Properties
Q jee_main_2025_29_jan_morning Periodic Trends in Physical and Chemical Properties
Given below are two statements : Statement (I) : The radii of isoelectronic species increases in the order: mathrm M g ^ 2 + < mathrm N a ^ + < mathrm F ^ - < mathrm O ^ 2 - Statement (II) : The magnitude of electron gain enthalpy of halogen decreases in the order: mathrm C l > mathrm F > mathrm B r > mathrm I
  • A. Statement I is incorrect but Statement II is correct
  • B. Both Statement I and Statement II are incorrect.
  • C. Statement I is correct but Statement II is incorrect
  • D. Both Statement I and Statement II are correct

Solution

### Related Formula textIonic Radius propto frac1textNuclear Charge (Z) quad text(for Isoelectronic series) ### Core Logic Evaluating each statement systematically : * Statement (I) is correct: mathrmMg^2+, mathrmNa^+, mathrmF^-, mathrmO^2- all possess exactly 10 electrons (isoelectronic). As the positive nuclear charge decreases (Z = 12 for mathrmMg down to Z = 8 for mathrmO), the nucleus exerts less pull on the electron cloud, causing the ionic radius to increase : mathrmMg^2+ < mathrmNa^+ < mathrmF^- < mathrmO^2- * Statement (II) is correct: Chlorine has a higher electron gain enthalpy magnitude than fluorine due to lower electron-electron repulsion in its larger 3p orbital. The standard halogen trend follows: mathrmCl > mathrmF > mathrmBr > mathrmI Thus, both statements are correct. ### Pattern Recognition For species with the same number of electrons, a higher negative charge always leads to a larger electron cloud radius due to reduced nuclear traction. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity in Properties
Q65 jee_main_2024_01_february_morning Ionic Radii
In case of isoelectronic species the size of F^-, Ne and Na^+ is affected by:
  • A. textPrincipal quantum number (n)
  • B. textNone of the factors because their size is the same
  • C. textElectron-electron interaction in the outer orbitals
  • D. textNuclear charge (z)

Solution

### Core Logic F^-, Ne, Na^+ all have 1s^2, 2s^2, 2p^6 configuration (10 electrons). However, their atomic numbers (nuclear charge, Z) are different: F: Z = 9 Ne: Z = 10 Na: Z = 11 Because they have the same number of electrons but different nuclear charges, the attraction between the nucleus and the valence shell electrons will differ. ### Step 1: Final Conclusion Higher nuclear charge strongly attracts the isoelectronic electron cloud, decreasing the ionic radius. Hence, their size is primarily affected by the nuclear charge (z). ### Pattern Recognition For isoelectronic species, size is inversely proportional to atomic number Z. The greater the Z, the smaller the size. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity in Properties
Q88 jee_main_2024_01_february_morning Periodic Trends in Chemical Properties
Among the following oxide of p-block elements, number of oxides having amphoteric nature is Cl_2O_7, CO, PbO_2, N_2O, NO, Al_2O_3, SiO_2, N_2O_5, SnO_2
Numerical Answer. Answer: 3 to 3

Solution

### Core Logic Let's classify the nature of each given oxide: - Cl_2O_7: Non-metal oxide in highest oxidation state rightarrow Strongly Acidic. - CO: Neutral oxide. - PbO_2: Heavy metal oxide near metalloid line rightarrow Amphoteric. - N_2O: Neutral oxide. - NO: Neutral oxide. - Al_2O_3: Classic amphoteric oxide. - SiO_2: Weakly acidic oxide. - N_2O_5: Non-metal oxide rightarrow Acidic. - SnO_2: Heavy metal oxide near metalloid line rightarrow Amphoteric. ### Step 1: Count Amphoteric Oxides The amphoteric oxides in the list are Al_2O_3, SnO_2, and PbO_2. Total count = 3. ### Pattern Recognition Memorize the main neutral oxides (N_2O, NO, CO) and the classic amphoteric oxides (Al_2O_3, ZnO, PbO, PbO_2, SnO, SnO_2, BeO, As_2O_3, Sb_2O_3). High oxidation state non-metals are always acidic. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity in Properties Class 12 Chemistry: The p-Block Elements
Q76 jee_main_2024_29_january_evening Ionization Enthalpy Trends
The element having the highest first ionization enthalpy is
  • A. Si
  • B. Al
  • C. N
  • D. C

Solution

### Related Formula textIonization Enthalpy (IE_1) propto frac1, textAtomic Size quad textand quad textStable configuration enhancements. ### Core Logic Analyzing periodic trends: 1. Ionization energy increases across a period from left to right and decreases down a group. 2. Nitrogen (N) and Carbon (C) belong to Period 2, while Aluminum (Al) and Silicon (Si) belong to Period 3. Consequently, Period 2 elements have smaller atomic radii and higher ionization energies. 3. Comparing Nitrogen and Carbon, Nitrogen (1s^2 2s^2 2p^3) has a highly stable, half-filled p-subshell configuration, giving it a much higher ionization energy than Carbon. ### Step 1: Trend Layout The overall first ionization enthalpy trend follows the sequence: mathrmAl < mathrmSi < mathrmC < mathrmN ### Pattern Recognition Nitrogen exhibits an exceptionally high first ionization energy due to its small size combined with a stable, half-filled 2p^3 valence subshell. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity
Rankbit System
JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)