Question

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Which of the following statements about ionization energy is true?
A. Ionization energy is the amount of energy used to add an electron to an atom.
B. Potassium has a lower ionization energy than sodium.
C. Elements toward the bottom of a group periodic table generally have higher ionization energies than elements at the top of the group.
D. In a period, elements farther to the right generally have lower ionization energies than elements on the left.