The variation of ionic radius with charge and electronic configuration is a fundamental concept in chemistry. Let's go through the explanation step by step:

1. Ionic Radius and Charge: Ions are formed when atoms lose or gain electrons. The loss of electrons results in a positive ion (cation), while the gain results in a negative ion (anion).
   • When a cation forms by the loss of electrons, the resulting positive charge increases the attraction between the electrons and the nucleus. This increased electrostatic attraction causes the ionic radius to decrease because the electrons are pulled closer to the nucleus.
   • On the other hand, gaining electrons to form an anion increases electron-electron repulsion and decreases the effective nuclear charge per electron, causing the ionic radius to expand.
2. Electronic Configuration: The electronic configuration of an ion also plays a role in determining its size.
   • Ions with similar electronic configurations can have different ionic radii because of the differences in nuclear charge. For example, \(Na^+\), \(Mg^{2+}\), and \(Al^{3+}\) all have the same electronic configuration as neon, but due to the increasing positive charge, \(Al^{3+}\) has the smallest radius, followed by \(Mg^{2+}\), and then \(Na^+\).
3. Conclusion: The correct statement is: "Higher positive charge leads to smaller ionic radius due to attraction." This captures the effect of increasing positive nuclear charge pulling electrons closer, thus reducing the ionic radius.

Let's consider the options given:

• Option 1: Higher positive charge leads to smaller ionic radius due to attraction — This is correct as explained.
• Option 2: Ionic radius remains constant regardless of ionic charge or structure — Incorrect, because the ionic radius changes with charge and structure.
• Option 3: Ionic charge has no influence on magnitude of ionic radius — Incorrect, as charge directly affects the ionic radius.
• Option 4: Electronic configuration plays no role in determining ionic size — Incorrect, since electronic configuration significantly impacts the size.

Hence, the correct answer is option 1: Higher positive charge leads to smaller ionic radius due to attraction.