Across • Aluminum • Atom • Atomic • Bottom • Calcium • Carbon • Chlorine • Decreases • Definition • Determine • Does • Down • Electrons • Element • From • Gold • Group • Helium • How • Identity • Increases • Iron • Lead • Left • Mass • Mercury • Move • Neon • Neutrons • Nitrogen • Nucleus • Number • Outermost • Oxygen • Particles • Period • Periodic • Position • Potassium • Protons • Reactivity • Relate • Related • Right • Shell • Sodium • Table • Top • Total