Final answer:
The correct order of first ionization energies for the elements Sr, Ba, Ca, Mg, and Be is B, which lists them from the lowest to the highest ionization energy as Sr > Ba > Ca > Mg > Be.
Step-by-step explanation:
The order of first ionization energies for the given elements can be predicted based on their positions in the periodic table . Ionization energie generally increases across a period (from left to right) and decreases down a group (from top to bottom). Therefore, within the same group, the larger atoms with more shells (which are found lower in the column) will have lower ionization energies because their outer electrons are farther from the nucleus and are more easily removed. Considering this, the correct order for these elements from lowest to highest ionization energy is: , Sr > Ba > Ca > Mg > Be.which corresponds to choice B in the question.