Which of the following properties indicate that an element is a metal. It I. reacts with oxygen to form an acidic oxide II. forms ionic chlorides III. has v...

Which of the following properties indicate that an element is a metal. It

I. reacts with oxygen to form an acidic oxide
II. forms ionic chlorides
III. has variable oxidation states
IV. displaces hydrogen from dilute HCl

Answer Details

Of the four properties listed, only II and IV are indicative of a metal. II. Metals tend to form ionic compounds with non-metals, such as chlorine. This is because metals have low electronegativity, so they are willing to lose electrons to form positively charged ions that can then combine with negatively charged ions like chloride ions. IV. Metals tend to displace hydrogen from dilute acids, which is a characteristic reaction of metals. When a metal reacts with an acid, it gives up electrons to hydrogen ions, forming hydrogen gas and a metal ion. This is called a single displacement reaction. I and III are not indicative of a metal. Non-metals tend to react with oxygen to form acidic oxides, and many non-metals can have variable oxidation states. Therefore, the correct answer is II and IV only.