Metals - Properties and Reactions

Metals are elements with specific properties and reactions.
Examples of metals include gold (Au), titanium (Ti), lead (Pb), zinc (Zn), iron (Fe), and copper (Cu).
Non-metals must be accompanied by a metal in chemical reactions.

Metals are conductors of heat and electricity.
Metals are malleable (can be shaped) and ductile (can be drawn into wires).
Metals have high density.
Metals are sonorous (make a ringing sound when struck).
Some metals are magnetic, such as iron, cobalt, and nickel; however, not all metals are magnetic.

Metallic bonding explains many physical properties of metals.
Electrons in the outer shells of metal atoms are free to move, forming a "sea of electrons."
Metal atoms are held together by their attraction to these free electrons.
Free electrons provide conductivity.
Close-packed structure leads to high density.

Metals are malleable and ductile because the bonds between atoms are not broken when the metal is deformed.
When a metal is hit, layers of atoms can move over each other due to the free-moving electrons.

Property	Metals	Non-metals
Appearance	Shiny	Dull
Electrical and Thermal Conductivity	Conductors	Insulators
Density	High	Low
Melting and Boiling Points	High	Low
Ductility	Yes	No
Malleability	Yes	No

General equation: Metal + Oxygen → Metal Oxide
Example: Sodium + Oxygen → Sodium Oxide
Some metals, like magnesium and calcium, burn in oxygen.
Some metals, like iron and copper, react slowly with oxygen (e.g., rusting of iron, formation of copper oxide).
Some metals, like silver, gold, and platinum, are inert or react very slowly with oxygen.

Some metals (magnesium, aluminum, zinc, iron) react with steam instead of water.
Metal Oxide is formed instead of Hydroxide.
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General equation: Metal + Acid → Metal Salt + Hydrogen
The salt formed depends on the type of acid used.
Example: Magnesium + Hydrochloric Acid → Magnesium Chloride + Hydrogen
Reactive metals like sodium, potassium and lithium should NEVER be added to acid due to the risk of explosion.
Some metals (copper, mercury, silver, gold) are inert to dilute acids, but copper and mercury can react with concentrated acids.

A series based on the difference in reactivity of metals.
Carbon and Hydrogen are NOT metals but act as indicators for metals’ reactivity.
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Order (Most to Least Reactive): Potassium (K) -> Sodium (Na) -> Calcium (Ca) -> Magnesium (Mg) -> Aluminum (Al) -> Carbon (C) -> Zinc (Zn) -> Iron (Fe) -> Tin (Sn) -> Lead (Pb) -> Hydrogen (H2) -> Copper (Cu) -> Mercury (Hg) -> Silver (Ag) -> Gold (Au) -> Platinum (Pt)

Definition: A more reactive metal will displace a less reactive metal from its compound.

Solid Displacement
- A more reactive solid metal displaces a less reactive solid metal compound.
- Example: Thermite Reaction
  - Equation: $Aluminium + iron\ oxide \rightarrow Aluminium \ oxide + iron$
  - Application: Source of molten iron for railway work (thermite welding for joining rails).
Solution Displacement
- A more reactive solid metal displaces a less reactive aqueous metal compound.
- Example: Silver Tree Reaction
  - Equation: $Copper + silver \ nitrate \rightarrow copper \ nitrate + silver$
  - Observation: Solution turns blue.
  - Application: Comparing the reactivities of different metals.

Metals are shiny and sonorous.
Metals are electrical and thermal conductors.
Metals are malleable and ductile.
Metallic bonding involves delocalized electrons surrounding positive metal ions.