Do atoms of a specific element contain the same number of protons

No, they don't because of fact some way more than the other even if it's the same type of element.

Explanation:

There are two types of element weight I think.

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Explanation:

"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."

with this one i know the answer in craters one reason i looked it up and i learned about it there is my evidence