The temperature at the boiling point remained constant despite the continued addition of heat by the bunsen burner. what was the energy used for? (as a side note, this energy is known as the enthalpy of fusion

Explanation:

Latent heat of fusion is defined as the heat necessary to change 1 g of a solid into liquid state without causing any change in temperature.

On the other hand, latent heat of vaporization is defined as the heat necessary to convert unit mass of a liquid into vapor state without any change in temperature.

So, at the boiling point both latent heat of fusion and latent heat of vaporization are in equilibrium with each other. Therefore, unless liquid does not changes completely into vapors there occurs no change in temperature.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."