The interior of the planets Jupiter and Saturn are believed to contain metallic hydrogen: hydrogen that is put under such tremendous pressure that it no longer exists as \(\mathrm{H}_{2}\), molecules, but instead exists as an extended metallic solid. Predict what properties metallic hydrogen might have compared to "normal" hydrogen in terms of first ionization energy, atomic size, and reactivity.

Normal hydrogen exists in molecular form (H2) and is a nonmetal. 1. First Ionization Energy: Hydrogen gas has a low first ionization energy because it only has one electron and one proton, making it relatively easy to remove the electron. 2. Atomic Size: Hydrogen is the smallest atom since it has only one electron and one proton. 3. Reactivity: Hydrogen gas is reactive because it readily forms a covalent bond with other atoms to achieve a stable electron configuration (e.g., combining with oxygen to form water).

Now, let's consider how hydrogen in a metallic state might affect its properties. 1. First Ionization Energy: In metallic hydrogen, the electrons would be delocalized in a "sea of electrons," which is typical for metallic bonding. This could lead to easier removal of electrons, causing a decrease in first ionization energy compared to hydrogen in its molecular form. 2. Atomic Size: In a metallic lattice, hydrogen atoms are packed closely together. Since there's a large force compressing the atoms, the atomic size of metallic hydrogen would likely be smaller than that of normal hydrogen. 3. Reactivity: As metallic hydrogen forms an extended metallic solid, its reactivity would likely decrease compared to normal hydrogen gas. This decreased reactivity may be due to the electrostatic attractions between the positive hydrogen nuclei and the delocalized electrons making it harder for other species to react with the hydrogen atoms present in the metallic solid.

In metallic hydrogen, compared to normal hydrogen: 1. First Ionization Energy: Metallic hydrogen would likely have a lower first ionization energy than normal hydrogen due to the delocalized electrons in the sea of electrons formed by metallic bonding. 2. Atomic Size: Metallic hydrogen would likely have a smaller atomic size than normal hydrogen since the atoms are compressed in a metallic lattice. 3. Reactivity: Metallic hydrogen would likely be less reactive than normal hydrogen due to the electrostatic attractions between the positive hydrogen nuclei and the delocalized electrons making it harder for other species to react with the hydrogen atoms present in the metallic solid.