Step 1: Analysis of Statement I
- The metallic radius of N a (neutral sodium atom) is 1.86 ̊A.
- The ionic radius of Na+ is smaller than the neutral atom because Na+ has one less electron, resulting in reduced electron-electron repulsion and greater effective nuclear charge on the remaining electrons. - Thus, Statement I is correct.
Step 2: Analysis of Statement II - While cations (Na+) are always smaller than their corresponding neutral atoms, anions (e.g., Cl-) are larger than their corresponding neutral atoms due to increased electron-electron repulsion in the outer shell.
- Hence, ions are not always smaller than the corresponding elements.
- Thus, Statement II is false.
Step 3: Conclusion - Statement I is correct, but Statement II is false.
Final Answer: (1)
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
Match List -I with List-II
| LIST-I (Atomic number) | LIST-II (Block of periodic table) |
|---|---|
| (A) 37 (K) | I. p-block |
| (B) 78 (Pt) | II. d-block |
| (C) 52 (Te) | III. f-block |
| (D) 65 (Tb) | IV. s-block |
Choose the correct answer from the options given below:
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,