Compare the reaction for the expansion of methane with the reverse of the reaction that represents the standard enthalpy of formation. Which properties are the same for both reactions and which are different?

answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.  

the electron configuration that you gave me has 16 electrons ergo it has 16 protons ergo it is the element sulfur.

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a