"atomic numbers" . . "protons" . "number of protons" . . "high-Z" . "atomic number, Z" . . . . "proton number" . . . . "Atomic Number" . "number of protons, Z" . "Number of atoms" . . "heavier elements" . . . . . . . "Z" . . "effective atomic number (Z)" . . "High-''Z''" . . . . "numbers of particles in atoms" . . "atomic number" . "Atomic number" . "atomic" . . "positive charge" . . . "z" . . . . "high-atomic weight" . "Atomic number" . . "''Z''" . .