I'm guessing D or C, remember that the noble gases cannot combine
<u>Answer:</u> The correct answer is Option D.
<u>Explanation:</u>
Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as 
The equation used to calculate enthalpy change is of a reaction is:
![\Delta H^o_{rxn}=\sum [n\times \Delta H^o_f_{(product)}]-\sum [n\times \Delta H^o_f_{(reactant)}]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28product%29%7D%5D-%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28reactant%29%7D%5D)
Hence, the correct answer is Option D.
1. option B
2. ground state Fe : [Ar] 4s² 3d⁶
<h3>
Further explanation</h3>
Aufbau rule
<em>Electrons occupy orbitals of the lowest energy level</em>
Charging electrons in the sub-shell uses the following sequence:
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.
So the correct choice of answer is B.
Ground state is the state of electrons filling skins with the lowest energy levels.
Excited state is the state of electrons which occupy a higher energy level
The atomic number of Fe = 26, so electrons=26
Ground state configuration of Fe : [Ar] 4s² 3d⁶ or
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d⁶