The question asks to identify the ion with the smallest ionic radius among the given options: Mg+2, Na+, Si+4, and Al+3.
All the given ions are isoelectronic, meaning they have the same number of electrons. Let's determine the number of electrons and protons (atomic number, Z) for each:
For isoelectronic species, the ionic radius decreases as the nuclear charge (number of protons) increases. A higher nuclear charge pulls the electron shells closer to the nucleus more effectively.
Comparing the nuclear charges, Si+4 has the highest nuclear charge (Z=14). Therefore, it attracts its 10 electrons most strongly, resulting in the smallest ionic radius.
The ion with the least ionic radius is Si+4 due to its highest nuclear charge among the isoelectronic species.
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Gypsum has lower density than anhydrite.
Reason (R) : Hydrated minerals tend to expand many times the original volume of the anhydrous minerals.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Drumlins show features opposite to those of Roches Moutonnees.
Reason (R) : The stoss side is steep and the lee side is roughened.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In a hand specimen quartz can be easily distinguished from orthoclase.
Reason (R) : Orthoclase has lower refractive index than quartz.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Chronostratigraphy is concerned with the mutual time relationship of strata.
Reason (R) : Formation, member and bed are units of chronostratigraphy.
In the light of the above statements, choose the most appropriate answer from the options given below :
Match List - I with List - II.
| List - I Mineral Property | List - II Type of light |
|---|---|
| A. Cleavage | I. Plane polarized |
| B. Twinkling | II. Ordinary |
| C. Twinning | III. Crossed nicols |
| D. Disperson | IV. Convergent |
Choose the correct answer from the options given below :
Match List - I with List - II.
| List - I Optical feature | List - II Optical diagram |
|---|---|
| A. Wave front (isotropic) | I. Ellipse |
| B. Wave surface (isotropic) | II. Sphere |
| C. Wave front (anisotropic) | III. ellipsoidal |
| D. Wave surface (anisotropic) | IV. circle |
Choose the correct answer from the options given below :