Answer:
The main difference between the two models is <em>the position of the electron in the atom</em>.
Explanation:
- <em>Bohr model:</em> The electrons are moved around the nucleus in circular definite paths (orbitals or shells). Also, he could not find or detect the exact position of electron.
- <em>Electron cloud model:</em> It is supposed by Erwin Schrodinger. He showed that the emission spectra of the atom is the way to detect the probability of electron position.
Answer : The internal energy change is, -506.3 kJ/mol
Explanation :
Formula used :

or,

where,
= change in enthalpy = 
= change in internal energy = ?
= change in moles
Change in moles = Number of moles of product side - Number of moles of reactant side
According to the reaction:
Change in moles = 0 - 2 = -2 mole
That means, value of
= 0
R = gas constant = 8.314 J/mol.K
T = temperature = 
Now put all the given values in the above formula, we get




Therefore, the internal energy change is -506.3 kJ/mol
C and B would be the answer because solid and gas are the same