Final answer:
Potassium, an element with an atomic number of 19 and a single valence electron, will most likely react with a nonmetal from group 17 of the periodic table, such as iodine, to form an ionic compound like potassium iodide (KI).
Step-by-step explanation:
Potassium (K), with an atomic number of 19, will most likely react with an element that can accept the electron it readily donates, due to its position in group 1 of the periodic table. Given that potassium has a single electron in its valence shell, it tends to form a positive ion (K+) by losing that electron, making it a cation. Thus, potassium would likely react with a nonmetal from group 17, also known as the halogens, which require one more electron to complete their valence shell.
Examining the periodic table provides insight into possible reactions. For instance, when considering the provided elements: sodium-24, aluminum-29, krypton-73, and iridium-194, we can predict potassium will not react with another metal (like sodium or aluminum) or noble gases (like krypton) since they are either also cations or inert. Iodine, a typical halogen, has a high affinity for electrons and is known for forming ionic bonds with alkali metals like potassium, as indicated by the formula KI, which represents potassium iodide, an ionic compound.
This shows the tendency of potassium to react with nonmetals such as iodine, which will result in an exothermic reaction, releasing energy when these atoms combine to form an ionic compound.