Final answer:
The charges of ions formed by cesium, magnesium, chlorine, and aluminum can be determined by their group numbers; cesium forms a 1+ cation, magnesium a 2+ cation, chlorine a 1- anion, and aluminum a 3+ cation.
Step-by-step explanation:
To determine the charge of ions derived from elements based on their group numbers on the periodic table, we can use simple rules. For cesium, being in group 1, it forms a cation with a 1+ charge (Cs+). Magnesium, in group 2, forms a cation with a 2+ charge (Mg2+). Moving on to chlorine, which is in group 17 (7 valence electrons), it gains an electron to achieve a full octet, resulting in an anion with a 1- charge (Cl-). Lastly, aluminum, which is in group 13, tends to lose all three of its valence electrons, forming an Al3+ cation. This process can be easily explained and predicted with the help of the periodic table.