## Chemistry: Molecular Approach (4th Edition)

In case of transition metals, electronegativity values generally increase from the first transition row to the second, and there is no further increase for the third row, which is different from the main group elements where the electronegativity values increase down the group. This is caused by the relatively small change in atomic size as we move down a column for the transition elements, accompanied by a large increase in nuclear charge. However, the trend of electronegativity across the period is same as the main group elements; that is, it increases across the period. So, gold $\left( Au \right)$, one of the heaviest metals, is the most electronegative metal.