Which nonmetal would an ion of ca2+ most likely ionically bond with in a 1: 1 ratio?

Explanation:

Atomic number of calcium is 20 and its electronic configuration is 2, 8, 8, 2.

Since it has two extra electrons, therefore, it donate these electrons to an electron deficient atom that needs only two electrons to complete its octet.

Oxygen atom has electronic configuration 2, 6. Hence, it is the atom that needs two electrons to complete its octet. So, it forms a compound of calcium oxide (CaO).

Thus, oxygen will most likely ionically bond with in a 1:1 ratio with .

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.