METALS & NON-METALS

LEARNING OBJECTIVES

• Identify the differences between metals and non-metals

• Describe the physical properties of metals and non-metals

• Understand the chemical properties and reactivity of each group

• Compare metals and non-metals based on their characteristics

• Predict the behaviour of elements based on their classification

  
  

KEY DEFINITIONS

• Metal: An element that conducts electricity, has a shiny appearance, is malleable and ductile, and typically forms positive ions

  
  

• Non-metal: An element that does not conduct electricity (except graphite), is dull in appearance,

  and typically forms negative ions or covalent bonds

  
  

• Malleability: Ability of a material to be beaten or pressed into different shapes without breaking

  
  

• Ductility: Ability of a material to be drawn out into thin wires

  
  

• Reactivity: How easily an element undergoes chemical reactions

  
  

PHYSICAL PROPERTIES OF METALS

• Appearance: Shiny and lustrous (except when tarnished)

• Melting point: Generally high (except mercury which is liquid at room temperature)

• Boiling point: Generally high

• Density: Generally high (most metals are dense)

• Electrical conductivity: Conduct electricity in solid state (electrons flow freely)

• Thermal conductivity: Good heat conductors

• Malleability: Can be beaten into thin sheets (copper, gold, aluminum)

• Ductility: Can be drawn into wires (copper, aluminum, iron)

• Solubility: Generally insoluble in water

• State at room temperature: Generally solid (Mercury is liquid)

CHEMICAL PROPERTIES OF METALS

Reaction with Oxygen (Combustion):

• Metals burn in oxygen forming metal oxides• Example: 2Mg + O₂ → 2MgO (bright white flame)

• Example: 2Cu + O₂ → 2CuO (black powder)

  
  

Reaction with Water:

• Reactive metals react with water producing hydrogen gas

• Example: 2Na + 2H₂O → 2NaOH + H₂ (vigorous reaction)

• Example: Mg + H₂O → MgO + H₂ (slow reaction)

• Less reactive metals do not react with water

  
  

Reaction with Acids:

• Metals react with dilute acids producing hydrogen gas

• Example: Zn + 2HCl → ZnCl2 + H2

• More reactive metals react faster

• Unreactive metals like copper do not react with dilute acids

  
  

Reactivity Series:

• Most reactive: K, Na, Ca, Mg, Al, Zn, Fe, Cu

• Least reactive: Ag, Au, Pt

• Position in series determines how easily metal loses electrons to form ions

PHYSICAL PROPERTIES OF NON-METALS

• Appearance: Dull (non-lustrous) - except diamond and iodine

• Melting point: Generally low (many are gases or liquids at room temperature)

• Boiling point: Generally low

• Density: Generally low

• Electrical conductivity: Do NOT conduct electricity (exception: graphite)

• Thermal conductivity: Poor heat conductors (insulators)

• Malleability: Brittle - break easily when hit

• Ductility: Cannot be drawn into wires - break under stress

• Solubility: Many soluble in water (e.g., oxygen, nitrogen)

• State at room temperature: Solid, liquid, or gas (variety of states)

CHEMICAL PROPERTIES OF NON-METALS

Reaction with Oxygen (Combustion):

• Non-metals burn in oxygen forming non-metal oxides

• Example: C + O₂ → CO₂ (burns with bright flame)

• Example: S + O₂ → SO₂ (burns with blue flame)

• Example: 2H₂ + O₂ → 2H₂O (explodes with pop sound)

  
  

Non-metal Oxides in Water:

• Form acidic solutions

• Example: CO₂ +H₂O → H₂CO₃ (carbonic acid)

• Example: SO₂ + H₂O → H₂SO₃ (sulfurous acid)

  
  

General Properties:

• Gain electrons to form negative ions

• Form covalent bonds with other non-metals

• Mostly non-reactive as elements but reactive in compounds

COMPARISON: METALS vs NON-METALS

EXAMPLES

Common Metals:

• Sodium (Na), Potassium (K), Calcium (Ca) - highly reactive

• Magnesium (Mg), Aluminum (Al), Zinc (Zn), Iron (Fe) - moderately reactive

• Copper (Cu), Silver (Ag), Gold (Au) - unreactive/noble metals• Mercury (Hg) - liquid metal at room temperature

  
  

Common Non-metals:

• Hydrogen (H), Oxygen (O), Nitrogen (N) - gases

• Fluorine (F), Chlorine (Cl), Bromine (Br) - halogens

• Carbon (C), Sulfur (S), Phosphorus (P) - solids

• Helium (He), Neon (Ne), Argon (Ar) - noble gases

  
  

Special Cases (Metalloids/Semi-metals):

• Silicon (Si), Boron (B), Arsenic (As)

• Have properties of both metals and non-metals

USES IN EVERYDAY LIFE

Metals:

• Copper - electrical wires, plumbing (conducts electricity and heat)

• Aluminum - aircraft, cooking foil (lightweight, malleable)

• Iron/Steel - building structures, tools (strong, durable)

• Gold/Silver - jewelry (unreactive, shiny)

  
  

Non-metals:

• Nitrogen - fertilizers (helps plant growth)

• Oxygen - respiration, combustion, medical use

• Sulfur - matches, rubber vulcanization

• Carbon - fuel, graphite for pencils, diamond for jewelry

• Chlorine - water purification, bleaching

  
  

Exam Question Format:

• Explain why copper is used in electrical wires while rubber is used as insulation

  
  

  Answer: Copper (metal) conducts electricity; rubber (non-metal) does not conduct

  
  

• Compare and contrast the properties of sulfur and iron

  
  

  Answer: Provide physical and chemical property differences using the table above