Final answer:
The elements francium, cesium, strontium, and calcium should be arranged in order of increasing ionization energy as follows: francium, cesium, strontium, calcium. This is based on the periodic trends where ionization energy increases across a period and decreases down a group.
Step-by-step explanation:
The question involves arranging the following elements according to their ionization energy: francium, cesium, strontium, and calcium. Ionization energy tends to increase across a period (from left to right) and decrease down a group (from bottom to top) in the periodic table. Therefore, we can predict the order of increasing ionization energy based on the positions of these elements in the periodic table.
To arrange the elements, we start with the element that would have the lowest ionization energy, which is francium (Fr), as it is the largest and most metallic of the given elements. Following that would be cesium (Cs), then strontium (Sr), and finally calcium (Ca), which is the smallest and least metallic of these elements. Hence, the correct order, from lowest to highest ionization energy, is:
- Francium (Fr)
- Cesium (Cs)
- Strontium (Sr)
- Calcium (Ca)