Which of the following species would require the highest energy for the removal
Mg
bNa
Ne
dF Which of the following has the lowest electronegativity?
Carbon
c Beryllium
b Magnesium
d Boron
Which of the following has the smallest radius?
a Na
c Mg
b Na
d Mg2+
The Correct Answer and Explanation is :
The correct answer is d) Mg²⁺.
To understand why, we need to look at the trends in ionic radius and how the number of protons and electrons in an atom or ion affects its size.
Atomic and Ionic Radius
The atomic radius is the distance from the nucleus to the outermost electron of an atom. When an atom forms an ion, its radius can change significantly based on whether the atom gains or loses electrons.
- Na (Sodium, atomic number 11): Sodium is in Group 1 of the periodic table, and it has an atomic number of 11. It has a single electron in its outermost shell, which it tends to lose to achieve a stable electron configuration similar to that of neon. The resulting ion, Na⁺, has 10 electrons and 11 protons.
- Mg (Magnesium, atomic number 12): Magnesium is in Group 2 of the periodic table, with an atomic number of 12. It has two electrons in its outermost shell, which it loses to form a Mg²⁺ ion, leaving it with 10 electrons and 12 protons.
Comparison of the Radii
- Na vs Na⁺: When sodium loses an electron to form Na⁺, the loss of the electron reduces electron-electron repulsion, leading to a smaller radius. However, Na⁺ still has 11 protons attracting 10 electrons, so its radius is relatively large.
- Mg vs Mg²⁺: Magnesium, when it loses two electrons to form Mg²⁺, has the same number of electrons as Na⁺ (10 electrons). However, because Mg²⁺ has 12 protons, the greater nuclear charge pulls the electrons closer to the nucleus, resulting in a smaller ionic radius compared to Na⁺.
Therefore, Mg²⁺ has the smallest radius among the given options because it has the most protons (12) pulling the same number of electrons (10) closer to the nucleus, creating a stronger effective nuclear charge and a smaller radius.
I will generate an image illustrating these concepts.
Here is the diagram comparing the atomic and ionic radii of sodium (Na), magnesium (Mg), sodium ion (Na⁺), and magnesium ion (Mg²⁺). As shown, Mg²⁺ has the smallest radius due to its higher nuclear charge pulling the same number of electrons closer to the nucleus. The image illustrates this concept visually. Let me know if you have any further questions!
