Reactions of Metals
Metal reactivity determines how vigorously metals react with oxygen, water, and acids. When metals react with oxygen, they form metal oxides - think about how iron rusts when exposed to air and moisture.
The most reactive metals like potassium and sodium react explosively with water, producing metal hydroxides (which are alkaline) and hydrogen gas. You can test for hydrogen because it burns with a distinctive "pop" sound when lit.
Acids react with metals to produce salts and hydrogen gas. The type of salt depends on the acid used: hydrochloric acid makes chlorides, sulfuric acid makes sulfates, and nitric acid makes nitrates. For example, zinc + hydrochloric acid → zinc chloride + hydrogen.
Remember: The reactivity series goes potassium, sodium, lithium, calcium, magnesium, zinc, iron, copper (most to least reactive). Carbon and hydrogen fit between zinc and iron.
Metal compounds also react with acids. Metal oxides and carbonates both react with acids, but carbonates also produce carbon dioxide gas, which turns limewater cloudy - a useful test you'll need to remember.
