Video Transcript
Which of the following elements can form a positive ion in an ionic compound? (A) 9F, (B) 16S, (C) 18Ar, (D) 20Ca, (E) 35Br.
An ionic compound is a compound composed of positively and negatively charged ions that are electrostatically attracted. Ionic compounds are formed when metal atoms like sodium react with nonmetal atoms like chlorine. During the reaction, the metal atoms lose electrons and the nonmetal atoms gain electrons. Metal atoms form positive ions when they lose electrons, and nonmetal atoms form negative ions when they gain electrons.
So to determine which of the elements can form a positive ion in an ionic compound, we need to identify which of the elements is a metal. Fluorine, sulfur, and bromine are nonmetals. These elements tend to form negative ions in an ionic compound. Argon is a noble gas. Noble gases do not tend to gain or lose electrons and do not form ions. Calcium is a metal that tends to lose two electrons during a chemical reaction and forms a Ca2+ ion.
In conclusion, the element that can form a positive ion in an ionic compound is answer choice (D), 20Ca.
