Question

why melting point of transition elements decreases as the atomic number increases?

Answer 1

For alkali metals and groups around the metalloids, both melting points and boiling points decrease with increasing atomic number. As atomic number increases, the points increases due to there being more electrons, which create a larger strength of negative charge around the nucleus of the atom.

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Answer 2

Transition metals have high melting points due to strong metallic bonds. Number of unpaired electrons in the outermost shell indicates the strength of the metallic bonds. Therefore, the more unpaired electrons are present, the higher melting point will be. The first 4 elements in a row always have the highest melting points. However, as the unpaired d orbital electrons pair up, the melting point decreases. The last 5 elements in a row have a lower melting point than the first 4 elements. The last element in each row has the lowest melting point because the d orbital electrons are filled.

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