Question

1 select the correct answer. the elements beryllium, calcium, and strontium are all in group 2. what is the correct relationship of these elements regarding their ionization energy?
a. ca < be < sr
b. sr < be < ca
c. be < ca < sr
d. sr < ca < be
e. ca < sr < be

Explanation:

Ionization energy (IE) is the energy required to remove an electron from an atom. For elements in the same group (group 2 here: Be, Ca, Sr), as we move down the group, the atomic radius increases because there are more electron shells. A larger atomic radius means the outermost electrons are farther from the nucleus and experience less effective nuclear charge, so they are easier to remove. Thus, IE decreases down a group. The order of these elements from top to bottom in group 2 is Be (period 2), Ca (period 4), Sr (period 5). So the ionization energy order is Sr (lowest) < Ca < Be (highest).

Answer:

D. Sr < Ca < Be