Which of the following compounds exhibits the highest covalent character?

The ascending order of polarizing power of the following ions is:
\(\mathrm{K}^{+}, \mathrm{Ca}^{2+}, \mathrm{Mg}^{2+}, \mathrm{Be}^{2+}\)

1. Mg²⁺ < Be²⁺ < K⁺ < Ca²⁺

2. Be²⁺ < K⁺ < Ca²⁺ < Mg²⁺

3. K⁺ < Ca²⁺ < Mg²⁺< Be²⁺

4. Ca²⁺ < Mg²⁺ < Be²⁺ < K⁺

The correct statement among the following is :
1.  (SiH₃)₃N is planar and more basic than (CH₃)₃N
2. (SiH₃)₃N is pyramidal and more basic than (CH₃)₃N
3.  (SiH₃)₃N is pyramidal and less basic than (CH₃)₃N
4. (SiH₃)₃N is planar and less basic than (CH₃)₃N