How many electron energy shells are occupied in an unstable atom of silicon

4

Explanation:

it will share its valence electrons with other elements to acquire noble gas confriguration of the nearest inert element.

Decrease their potential energy and increase kinetic energy. The electric field is similar to gravitational field. In a gravitational field, an object will fall to decrease its potential energy. However, total energy is conserved. Therefore, the kinetic energy must increase since PE+KE is constant.