Because of their repulsion, the clouds of electrons 13 & 14 would like to move farther apart.
This repulsive force drives not only these electrons, but also electrons 11 & 12, to reorganize themselves as shown here.
The final arrangement yields a tetrahedron of four outer "valence" or bonding electrons spaced symmetrically (by 109 degrees) around the atom core.
The core (with 14 positive protons and 10 negative electrons) carries a net charge of +4, precisely balancing the -4 charge of the bonding electrons.
