Answer:
Out of the pairs you've given, the atom with the greater ionization energy is:
Barium (Ba)
Ionization energy is the energy required to remove an electron from an atom, and it increases as you move from left to right across a period (row) of the periodic table. Barium has an ionization energy of 5.85 eV, while Be has an ionization energy of 5.5 eV, Al has an ionization energy of 5.9 eV, and Cl has an ionization energy of 7.6 eV. Therefore, Ba has the greatest ionization energy among the four options.
Step-by-step explanation: