[Tex/LaTex] Atomic Structure in LaTeX

Question

I used the bohr package to draw the atomic structure of silicon atom.

1. Is it possible that the outer 4 electrons appears distributed symmetrically (left, right, top, bottom).
2. How to show only Si-core and the outer 4 electrons, i.e., I want Si in a small circle at the centre surrounded by another circle with 4 outer electrons.
3. Is there any package which helps in showing one Si-atom surrounded by four neighbouring Si-atoms with all the 4 electrons of central Si-atom sharing electrons from neighbouring Si-atoms.

Something like this

Answer 1

Just draw it yourself using TikZ. I extracted the drawing options from the bohr package to match the looks.

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[
  baseline=(nucleus.base),
  nucleus options/.style = {draw=black!80,fill=black!10,opacity=.25},
  shell options/.style = {draw=blue!75,thin},
  electron options/.style = {blue!50!black!50},
  silicon/.pic = {
    \node (nucleus) at (0,0) {Si};
    \draw[nucleus options] (nucleus) circle (1em);
    \draw[shell options] (nucleus) circle (2em);
    \foreach \angle in {0,90,180,270} {
      \fill[electron options] (nucleus) ++(\angle:2em) circle (1.5pt);
    }
  },
  ]
  \foreach \angle in {0,90,180,270} {
    \fill[lightgray,rotate=\angle] (2.5em,0) ellipse (1em and .5em);
    \path (\angle:5em) pic {silicon};
  }
  \path (0,0) pic {silicon};
\end{tikzpicture}
\end{document}