The answer to your question is D. send the message underwater because a more dense medium produces a louder and faster sound.
It’s hard which class are u
Ionic compounds are compounds that are formed together by a cation and an anion. A cation is an ion with a positive charge. For example, Na+ and Ca2+. An ion has a negative charge, like Cl- and OH-. There is a greater chance of forming an ionic compound when they have a great difference in electronegativity, the ability to attract electrons toward itself. In the periodic table, elements that are opposite to each other, more likely found in opposite sides, would be more apt to form an ionic compound. Example would be NaCl and CaCl2 or Ca(OH)2.
B.it is not balanced for charge or for number of atoms.
