Based on silicon's position on the periodic table, it has a. 14 electrons, which include 4 valence electrons in the third energy level and 10 electrons distributed over the first two energy levels. b. 14 electrons, which include 2 valence electrons in the third energy level and 12 electrons distributed over the first two energy levels. c. 14 valence electrons distributed over three energy levels. d. 14 electrons, which include 10 valence electrons in the second energy level and 4 electrons in the first energy level.

A. 14 electrons, which include 4 valence electrons in the third energy level and 10 electrons distributed over the first two energy levels.

Explanation:

Silicon is an element with atomic number 14 and thus contain 14 electrons. It is a p block element as the last electron enters the p orbital. The nearest noble gas is neon with 10 electrons.

The electrons are filled according to Afbau's rule in order of increasing energies and thus the electronic configuration in terms of noble gs configuration is:  

The valence electrons are the electrons present in last shell i.e n= 3, thus there are 4 valence electrons, 8 electrons in n= 2 and 2 electrons in  n= 1 energy level. Thus total of 10 electrons in first two energy levels.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.