Silicon is a chemical element with the symbol Si, atomic number 14 and relative atomic
mass 28. So, in our case X is the Silicon (Si).
Silicon-28 is a stable isotope of Silicon with N = A – Z = 28 – 14 = 14 neutrons in the
nucleus. The electronic distribution of Silicon is 1s2
Silicon is a metalloid – value of his electronegativity is intermediate between metals and
non-metals. Also on the outer energy level of Silicon atom there are four valent electrons, and
it may react with both metals or non-metals to form four covalent bonds and stable electron
octet configuration on the outer energy level.