Metals, Non-metals & Periodic Table

• Study notes for end of term revision

Metals vs Non-metals

• Metals*
• Good conductors of heat and electricity
• Shiny
• High density
• Ductile (can be pulled into wires)
• Sonorous (makes a ringing sound when hit)
• Examples: Iron, Copper, Gold
• Non-metals*
• Poor conductors of heat and electricity
• Dull
• Low density
• Brittle (breaks easily)
• Not sonorous
• Examples: Oxygen, Chlorine, Sulfur

Metalloids

• Elements near the stepped line that separates metals and non-metals
• Properties are between those of metals and non-metals (e.g., Mercury)

Periods

• Horizontal rows of the periodic table
• Going across a period, there are patterns in the properties of the elements

Groups

• Vertical columns in the periodic table
• Elements in a group have similar properties
• Metals are on the left side of the periodic table, non-metals on the right

Group 1 (Alkali Metals)

• Alkali metals are very reactive
• Softness, reactivity, and density increase from top to bottom
• Boiling and melting points decrease from top to bottom
• Good conductors of electricity and heat
• Shiny when freshly cut
• Uses:
• Lithium is used in batteries and psychiatric medications
• Sodium is used in street lights and as a food preservative

Reactions with Water

• Creates Alkaline solutions

Group 7 (Halogens)

• They are metals
• Reactivity decreases from top to bottom
• Melting and boiling points increase from top to bottom
• Color of the elements gets darker from top to bottom
• Do not conduct electricity
• Reactive elements
• Low melting and boiling points

Chemical Properties

• All group 7 elements react with iron iron + chlorine → iron chloride
• iron + bromine → iron bromide
• iron + iodine → iron iodide
• Uses:
• Fluorine is used in water treatment and toothpaste
• Chlorine is used in water purification and swimming pools

Displacement

• A displacement reaction occurs when a more reactive element takes the place of a less reactive element in a compound
• chlorine + potassium bromide → potassium chloride + bromine

Group 8/0 (Noble Gases)

• Non-metals
• Slightly more reactive from top to bottom
• Boiling point increases from top to bottom
• Don't conduct electricity
• Low melting and boiling points
• Unreactive elements
• Glow brightly under high voltage

Group 8/0 Uses

• Helium is used in party balloons and MRI machines
• Neon is used in neon signs and lighting
• Scientists call group 8/0 unreactive
• Xenon forms compounds with fluorine and oxygen
• Krypton reacts with fluorine to make krypton difluoride

Mixtures

• Two or more elements or compounds not chemically joined
• Easily separated; Elements keep their own properties and quantities of substances in a mixture

Elements

• Substances made from the same type of atom

Compounds

• Substances with two or more different elements chemically bonded

Pure Substances

• Made from only one element or compound
• Melt and boil at a sharp point

Mixtures vs Compounds

• Mixtures*
• Substances not joined together
• Keep their own properties
• Easy to separate
• Amount of each substance can be changed
• Compounds*
• Substances are joined
• Have different properties
• Require chemical reactions to separate
• The relative amount of each substance cannot change

Solutions

• Solvent: A liquid that dissolves a substance (e.g., water/ethanol)
• Solute: A substance that dissolves into a solvent (e.g., sodium chloride/sugar)
• Solution: A mixture of a solvent and solute Solute + Solvent → Solution
• Salt + Water → Sea Water
• Soluble: A substance that can dissolve (e.g., sugar)
• Insoluble: A substance that cannot dissolve (e.g., rocks)

Dissolving

• Process of a solute mixing with a solvent and disappearing
• Sugar dissolving into water
• For fair results, use the same temperature, mass of solute, and volume of solvent

Solubility

• The maximum amount of a substance that can dissolve in 100g of water at a given temperature to form a saturated solution
• Water is known as a universal solvent because most solutes dissolve in it
• Saturated solution: Contains the maximum mass of a solute that can dissolve at a given temperature; any extra solute remains undissolved
• Unsaturated solution: solute is below the saturated point; more can dissolve
• Saturated Solution: Dissolve solute is at saturation point; no more solute can dissolve in it
• Super Saturated: The dissolved solute is above the saturated point; additional solute gathers at the bottom
• Saturation point: The point where no more solute will dissolve; reached the maximum mass of solute

Factors Affecting Solubility

• Temperature: Solubility increases with temperature for most substances
• Nature of the solute and solvent: Different substances dissolve to different extents in water

Filtration

• Separating solids from liquids or gases by passing them through a filter medium
• Purpose: to remove unwanted particles from a liquid/gas
• Filtrate: Liquid or gas that passes through the filter
• Residue: Solid particles that are retained on the filter medium

Process of Filtration

• Add water to the mixture, stir, salt dissolves, sand doesn't
• Pour the mixture into a filter paper funnel
• Salt solution passes through the paper
• Residue is sand

Uses of Filtration

• Separating coffee solution from coffee beans
• Oil filters in cars remove dirt from the engine oil to prevent engine damage
• Sand filters help make water safe to drink
• Filter paper allows only the liquid to pass through because the filter paper's pores are smaller than the solid particles

When is Filtration Used?

• To separate a solution from an insoluble solid

Evaporation

• Process where a liquid changes into a gas (vapor) below its boiling point
• Happens when molecules at the surface of the liquid gain enough energy to break free and become gas
• It is a slow process and can occur at any temperature

How can Salt be separated from Seawater?

• Salt can be separated from seawater through evaporation
• When seawater is heated, the water evaporates, leaving the salt behinds
• Uses:
• Drying clothes
• Salt production
• Drying of glue

Distillation

• Separating a mixture of liquids based on their different boiling points
• Uses separation and condensation to obtain a solvent from a solution
• Simple Distillation: Used for separating liquids with significantly different boiling points
• Fractional Distillation: Used when boiling points are closer; a fractionating column is used to let the gas with the lower boiling point through

Distillation Uses

• Purifying water
• Oil refining
• Separation of gases

How Distillation Works

• Water in the salt solution heats up and boils
• Steam rises and leaves the solution
• Steam passes through the condenser, where it cools down
• As it cools, the steam condenses back into liquid water
• Liquid water then drips into the beaker

Chromatography

• A method used to separate mixtures of liquids that are soluble in the same solvent

How Chromatography Works

• Small sample of the mixture (like ink or plant pigment) is placed on a surface (usually chromatography paper)
• A solvent (liquid) is then allowed to move up the paper by capillary action
• Different components of the mixture move at different rates and separate from each other

Factors Affecting Chromatography

• Solvent (Type of solvent can change how the substances separate)
• Paper Type
• Distance traveled

Types of Chromatography

• Paper Chromatography: Uses a strip of paper to separate substances based on solubility
• Thin Layer Chromatography (TLC): Uses a thin layer of adsorbent (like silica gel) on a plate
• Column Chromatography: Involves passing the mixture through a column packed with adsorbent
• Gas Chromatography: Separates gases and vapors using a column and inert gas

Chromatography Applications

• Forensic science: Identifying drugs
• Food industry: Detecting food coloring
• Environmental Science: Identify pollutants in water
• Pharmaceutical Industry: Used in drug/medicine development
• Mobile Phase: The substance that moves through the stationary phase (water)
• Stationary Phase: The substance or material that stays fixed in place (chromatography paper)
• Chromatogram: Result produced after performing chromatography
• Solvent front: Where the solvent stops going up

Acids and Metals

• Concentrated Solution*
• A mixture containing a large amount of solute dissolved in a relatively small amount of solvent
• Dilute Solution*
• A mixture with a small amount of solute dissolved in a relatively large amount of solvent
• Reactivity of Metals (Most reactive to non-reactive)*
• Magnesium
• Zinc
• Iron
• Lead
• Copper
• Silver and Gold (Inert Metals)

Inert Metals

• Metals that don't react with acids, oxygen, and water
• Silver and gold

Acids Equations

• Metal + Acid → Salt + Hydrogen Gas

Hydrochloric Gas Equations

• Zinc + Hydrochloric Acid → Zinc Chloride + Hydrogen
• Calcium + Hydrochloric Acid → Calcium Chloride + Hydrogen
• Lead + Hydrochloric Acid → Lead chloride + Hydrogen

Sulfuric Acid Equations

• Potassium + Sulfuric Acid → Potassium sulfate + Hydrogen
• Magnesium + Sulfuric Acid → Magnesium Sulfate + Hydrogen
• Zinc + Sulfuric Acid → Zinc Sulfate + Hydrogen

Nitric Acid Equations

• Zinc + Nitric Acid → Zinc Nitrate + Hydrogen
• Magnesium + Nitric Acid → Magnesium Nitrate + Hydrogen
• Potassium + Nitric Acid → Potassium Nitrate + Hydrogen

Pop Test

• When magnesium and hydrochloric acid react, magnesium chloride and hydrogen gas are produced
• Collect the hydrogen gas using an empty, inverted test tube
• Hold a lit splint to the test tube containing the collected gas; a squeaky pop sound confirms the presence of hydrogen gas

Comparison of Reactions

• Hydrochloric Acid: Reacts with most metals to form chloride salts and hydrogen
• Sulfuric Acid: Reacts similarly to hydrochloric acid, forming sulfate salts
• Nitric Acid: Forms nitrate salts with reactive metals but tends to be less vigorous

Metals and Oxygen

• Metals react with oxygen to form metal oxides
• The general equation for a metal-oxygen reaction is: Metal + Oxygen → Metal oxide
• This reaction varies depending on the metal used

Reaction with Oxygen

• Metal + Oxygen → Metal oxide
• Calcium + Oxygen → Calcium oxide
• Zinc + Oxygen → Zinc Oxide
• Potassium + Oxygen → Potassium Oxide
• Iron + Oxygen → Iron Oxide

Reaction with Dilute Acid

• Magnesium Reacts very vigorously
• Zinc Reacts steadily
• Iron Reacts steadily
• Lead Reacts slowly
• Copper No reaction
• Gold and Silver No reaction

Reaction with Oxygen

• Magnesium Burns Vigorously
• Zinc Burns less vigorously
• Iron Burns
• Lead Do not burn when heated; Forms layer of oxide on surface
• Copper Do not burn when heated; Forms layer of oxide on surface
• Gold and Silver No reaction

Reacting Sodium with Oxygen

• Needs a little heat to burst into yellow flames and burn quickly to produce a new substance in the form of white powder
• Reacting Magnesium with Oxygen: Produces white lighting, and a white powder is left behind
• Reacting Zinc with Oxygen: Produces an orange flame, and a white powder is left behind
• Reacting iron with Oxygen: Iron wire, called iron wool, glows and produces yellow sparks; a black powder is left behind
• Reacting of Copper with Oxygen: Develops a covering of black powder without glowing or bursting into flames

Metals and Water

• Metals react with water to form metal hydroxides and hydrogen
• The general equation for a metal-water reaction is: Metal + Water → Metal hydroxide + Hydrogen

Metal + Water

• Metal + Water → Metal Hydroxide + Hydrogen
• Zinc + Water → Zinc Hydroxide + Hydrogen
• Calcium + Water → Calcium Hydroxide + Hydrogen
• Lead + Water → Lead Hydroxide + Hydrogen

State Symbols

• (s) solid
• (l) liquid
• (g) gas
• (aq) aqueous solution
• Examples:*
• copper strips
• water
• oxygen
• salty water