Final answer:
Helium (He) has the highest first ionization energy due to its position in the periodic table, having tightly bound electrons that are difficult to remove.
Step-by-step explanation:
The atom with the highest first ionization energy is helium (He). Ionization energy is the energy required to remove the most loosely bound electron from an atom in its gas phase. Generally, ionization energy increases across a period and decreases down a group in the periodic table. Helium, being in the top right corner of the periodic table (except for the noble gases), holds its electrons more tightly than hydrogen (H), lithium (Li), and beryllium (Be), making its electrons the most difficult to remove.