Classification of Elements and Periodicity in Properties

A monoatomic anion $(\mathrm{A^-})$ has 45 neutrons and 36 electrons. Atomic mass, group in the periodic table and physical state at room temperature of the element (A) respectively are

The 1$^{\text{st}}$ ionization enthalpy for Mg is +737 kJ/mol. The most probable estimated value of the 2$^{\text{nd}}$ ionization enthalpy of Mg is ______.

Given below are two statements: Statement I: The correct order of electronegativity of fluorine, oxygen and nitrogen is F > O > N. Statement II: The oxidation state of oxygen in $\mathrm{OF_2}$ is +2 and in $\mathrm{Na_2O}$ is $-2$. In the light of the above statements, choose the correct answer from the options given below

Given below are two statements : Statement I : The number of pairs among $[\mathrm{Al_2O_3, Cr_2O_3}]$, $[\mathrm{Cl_2O_7, Mn_2O_7}]$, $[\mathrm{Na_2O, V_2O_3}]$ and $[\mathrm{CO, N_2O}]$ that contain oxides of same nature (acidic, basic, neutral or amphoteric) is 4. Statement II : Among $\mathrm{Na_2O}$, $\mathrm{Al_2O_3}$, CO and $\mathrm{Cl_2O_7}$, the most basic and acidic oxides are $\mathrm{Na_2O}$ and $\mathrm{Cl_2O_7}$, respectively. In the light of the above statements, choose the correct answer from the options given below :

First and second ionization enthalpies of lithium are 520 kJ mol$^{-1}$ and 7297 kJ mol$^{-1}$ respectively. Energy required to convert 3.5 mg lithium (g) into $\mathrm{Li^{2+}(g)}$ $[\mathrm{Li(g)\to Li^{2+}(g)}]$ is ________ kJ mol$^{-1}$. (nearest integer) [Molar mass of Li = 7 g mol$^{-1}$]

Match List - I with List - II. List - I (Electronic configuration of neutral atom (where n = 2)): A. $ns^2$; B. $ns^2np^1$; C. $ns^2np^3$; D. $ns^2np^6$. List - II (1$^{st}$ Ionization Energy (kJ mol$^{-1}$)): I. 2080; II. 899; III. 800; IV. 1402. Choose the correct answer from the options given below :

Match List-I with List-II. List-I: (A) $\mathrm{Al^{3+}<Mg^{2+}<Na^{+}<F^{-}}$ (B) B < C < O < N (C) B < Al < Mg < K (D) Si < P < S < Cl. List-II: (I) Ionisation Enthalpy (II) Metallic character (III) Electronegativity (IV) Ionic radii. Choose the correct answer from the options given below:

Which of the following electronegativity order is incorrect?