Sodium, atomic number 11, forms an ionic bond with an atom of an unknown element. what is one possible choice for the other element in the compound?

An ionic bond is a kind of chemical bond produced via an electrostatic association between the two oppositely charged ions. Ionic bonds are produced between a cation, that is, generally a metal, and an anion, that is, generally a non-metal. A covalent bond involves a pair of electrons being shared among the atoms.

For example, consider sodium cations and chlorine anions. Sodium has a positive 1 charge and chloride has a negative 1 charge. Thus, one sodium cation cancels one chloride anion leading to the formation of NaCl.

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