Select all the true statements. Group of answer choices In the transition series, atomic size across a period decreases at first but then remains relatively constant. First ionization energy values generally increase down a transition group. Ionic bonding is more prevalent for the higher oxidation states and covalent bonding is more prevalent for the lower states. The transition elements in a period show a steady increase in electronegativity. The highest oxidation state of elements in Groups 3A through 7B is 3.