Metals and Non-metals - CHEMIC3.2 CHEMIC3.2 CHEMIC3.2 CHEMIC3.2 CHEMIC AL PROPERTIES OF METAL PROPERTIES OF METAL PROPERTIES OF METAL PROPERTIES OF METAL PROPERTIES OF MET ALS ALSALS ALSALS

Reaction with Oxygen: Metals react with oxygen to form metal oxides. These are generally basic in nature, meaning they turn red litmus blue. For example, $2Mg + O_2 \rightarrow 2MgO$.

Amphoteric Oxides: Some metal oxides, such as aluminum oxide ($Al_2O_3$) and zinc oxide ($ZnO$), show both acidic and basic behaviors. They react with both acids and bases to produce salt and water.

Reaction with Water: Metals react with water to produce metal oxides or hydroxides and hydrogen gas ($H_2$). Sodium ($Na$) and Potassium ($K$) react violently with cold water, while Iron ($Fe$) only reacts with steam: $3Fe(s) + 4H_2O(g) \rightarrow Fe_3O_4(s) + 4H_2(g)$.

Reaction with Acids: Metals react with dilute acids to form salt and hydrogen gas. However, metals do not usually evolve $H_2$ with dilute $HNO_3$ because it is a strong oxidizing agent that oxidizes $H_2$ to $H_2O$.

Reactivity Series: Metals are arranged in a series based on their reactivity. A more reactive metal (e.g., $Zn$) can displace a less reactive metal (e.g., $Cu$) from its salt solution: $Zn(s) + CuSO_4(aq) \rightarrow ZnSO_4(aq) + Cu(s)$.

Aqua Regia: A highly corrosive mixture of concentrated hydrochloric acid ($HCl$) and concentrated nitric acid ($HNO_3$) in a ratio of $3:1$, capable of dissolving gold and platinum.