Concept:Metals are electropositive elements that form basic oxides, ionic compounds, and displace hydrogen from dilute acids.
Explanation:Metals react with oxygen to form basic oxides, not acidic oxides.
Therefore statement I is incorrect.
Metals typically lose electrons and form ionic chlorides, such as
NaCl.
Therefore statement II is correct.
Variable oxidation states are common among transition metals but are also seen in non-metals, so this is not a reliable metallic property.
Therefore statement III is incorrect.
A metal above hydrogen in the activity series displaces hydrogen gas from dilute
HCl.
Therefore statement IV is correct.
Hence, the metallic properties are only II and IV.
Answer:Option C. II and IV only.