If a color change occurs when two solutions are mixed is it true that a chemical react has probably taken place?

yes

Explanation: When you mix an acid an a base the color it showing a chemical change.

Yes it is true

Explanation:

It is most likely a change has occurred with the PH of the solutions and it is a common indicator of a chemical reaction.

"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."