The element that does not belong to the same period of the remaining elements (modern periodic table) is:

<p>Let's analyze the periods for each element:</p> <p><p>Platinum (Pt) has an atomic number of 78, which places it in period 6.</p></p> <p><p>Osmium (Os) has an atomic number of 76, also in period 6.</p></p> <p><p>Iridium (Ir) has an atomic number of 77, which is in period 6 as well.</p></p> <p><p>Palladium (Pd) has an atomic number of 46, placing it in period 5.</p></p> <p>Since Palladium is in period 5 while the other elements are in period 6, the element that does not belong to the same period is:</p> <p>$\textbf{Option D: Palladium.}$</p>