Question

question 3 (5 points)
which has an ionic potential less than 10 nm^-1 (low charge, large radius)
ti
si
c
k
al
question 4 (5 points)
eight - fold coordination is also known as?

Explanation:

Step1: Recall ionic potential concept

Ionic potential ($\phi$) is related to charge - to - radius ratio ($\frac{Z}{r}$). Elements with low charge and large radius have low ionic potential.

Step2: Analyze each element

• Ti: Titanium can form ions with relatively high charges (e.g., Ti$^{4 +}$) and has a relatively small ionic radius compared to some other elements, so its ionic potential is not low.
• Si: Silicon can form Si$^{4+}$ ions. It has a small atomic and ionic radius, so its ionic potential is high.
• C: Carbon can form C$^{4+}$ in some cases. It has a very small atomic and ionic radius, resulting in a high ionic potential.
• K: Potassium forms K$^{+}$ ion. It has a large atomic and ionic radius and a low charge (+ 1). So, its ionic potential is low.
• Al: Aluminum forms Al$^{3+}$ ion. It has a relatively small ionic radius and a + 3 charge, so its ionic potential is not low.

Answer:

K