Question

which is the correct order for the names and formulas of binary ionic compounds?
a metal anion followed by nonmetal cation
b nonmetal cation followed by metal anion
c nonmetal anion followed by metal cation
d metal cation followed by nonmetal anion

Explanation:

Binary ionic compounds are formed from a metal (which loses electrons to form a cation, a positively - charged ion) and a non - metal (which gains electrons to form an anion, a negatively - charged ion). When naming or writing the formula of a binary ionic compound, the metal cation (positive ion) is written or named first, followed by the non - metal anion (negative ion).

• Option a: Metals form cations (not anions) and non - metals form anions (not cations), so this is incorrect.
• Option b: Non - metals form anions (not cations) and metals form cations (not anions), so this is incorrect.
• Option c: The order is reversed; the metal cation should come before the non - metal anion.
• Option d: This follows the correct rule for binary ionic compounds, where the metal cation (from the metal atom losing electrons) is followed by the non - metal anion (from the non - metal atom gaining electrons).

Answer:

d. metal cation followed by nonmetal anion