Given the reaction at STP and at equilibrium: H2(g) + Cl2(g) → 2 HCl(9)
Which change will result in an increase in the
concentration of Cl2(g)?
A) decreasing the pressure of the system
B) decreasing the concentration of HCl(g)
C) increasing the concentration of H2(g)
D) increasing the concentration of HCl(9)

the answer is na (sodium)

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)