Metals react with oxygen to form metal oxides. The type of oxide formed depends on the metal's reactivity and the conditions of the reaction. The reaction can be spontaneous or require heating.

• Highly Reactive Metals (e.g., Sodium, Potassium): React vigorously with oxygen to form oxides. Sodium forms sodium oxide (Na₂O), and potassium forms potassium peroxide (K₂O₂).
• Moderately Reactive Metals (e.g., Magnesium, Aluminium): React with oxygen to form metal oxides. Magnesium forms magnesium oxide (MgO), and aluminium forms aluminium oxide (Al₂O₃).
• Less Reactive Metals (e.g., Iron, Copper): React with oxygen to form metal oxides, but the reaction is often slow and requires heating. Iron forms iron(III) oxide (Fe₂O₃), and copper forms copper(II) oxide (CuO).

The oxides formed can be basic or acidic, depending on the metal. For example, sodium oxide (Na₂O) is a strong base, while aluminium oxide (Al₂O₃) is amphoteric (can react with both acids and bases). The formation of a protective oxide layer on the surface of some metals (e.g., aluminium, chromium) prevents further reaction with oxygen.

Malleability: Metals are generally malleable, meaning they can be hammered or rolled into thin sheets without breaking. This is due to the metallic bonding, which allows the metal atoms to slide past each other without disrupting the overall structure. Non-metals are typically brittle and shatter when hammered or rolled. Their bonding is often covalent or ionic, which does not allow for easy rearrangement of atoms.

Ductility: Metals are also generally ductile, meaning they can be drawn into wires without breaking. This is again due to the metallic bonding, which allows the metal atoms to be extended into a continuous strand. Non-metals are usually brittle and do not possess ductility.

Examples:

• Malleable Metals: Gold, Silver, Copper
• Malleable Non-metals: Graphite (can be powdered into a soft, pliable substance)
• Ductile Metals: Copper, Iron, Aluminium
• Ductile Non-metals: (Generally not ductile. Some polymers can be drawn into fibres, but this is not the same as ductility in metals.)

The reactivity of metals with cold water and steam varies significantly. Some metals react vigorously, some react slowly, and some do not react at all. The reactivity is generally related to the metal's position in the reactivity series.

• Highly Reactive Metals (e.g., Sodium, Potassium): React vigorously with cold water, producing hydrogen gas and a metal hydroxide. The reaction can be exothermic and potentially dangerous.
• Moderately Reactive Metals (e.g., Magnesium, Calcium): React with steam, but the reaction is slower than with cold water. They produce hydrogen gas and a metal oxide.
• Less Reactive Metals (e.g., Iron, Zinc): Generally do not react with cold water or steam under normal conditions. However, they may react slowly if the surface is not clean.

The reaction with steam is a specific case of a reaction with water, where the water is in the gaseous phase. The products are similar to those formed with cold water, but the reaction rate can be slower.