C9. The Periodic Table Flashcards
Group 1 alkali metals - physical properties
- Very soft and can be cut easily with a knife
- Low MP and BP
- Low density (can float on water)
Group 1 alkali metals - trends down the group
- Softer
- MP decreases
- Density increases
- More reactive
Group 7 halogens - physical properties
- Form coloured gases (low density)
- Form diatomic molecules
- Low MP and BP
- Poisonous
Group 7 halogens - trends down the group
- Colour gets darker
- BP increases
- Density increases
- Less reactive
Group 7 halogens - colours in water/cyclohexane
- Chlorine - colourless in water/cyclohexane
- Bromine - orange in water/(darker) in cyclohexane
- Iodine - red-brown in water/purple in cyclohexane
Group 7 halogens - colours in potassium bromide/potassium iodide
- Aqueous chlorine in aq KBr - colourless solution turns red-brown (orange w/ cyclohexane)
- Aqueous chlorine in aq KI - colourless solution turns brown (purple w/ cyclohexane)
- Aqueous bromine in aq KI - colourless solution turns brown (purple w/ cyclohexane)
Group 8 noble gases - physical properties
- Colourless, monatomic gases
- Inert
- Low BP
Group 8 noble gases - trends down the group
- Size of atom increases
- Density increases
- BP increases
Group 8 noble gases - uses
- Helium - fill balloons and airships
- Argon (provide an inert atmosphere) - filler in tungsten light bulbs, welding of metals carried out in atmosphere of argon
- Neon - advertising signs
- Krypton - lasers, car headlamps
- Xenon - car headlamps, natural anaesthetic
- Radon - radiotherapy
Transition elements - physical properties
- Hard, strong, high density
- High MP (except mercury)
- Malleable and ductile
- Good conductors of heat and electricity
- Shiny
- Sonorous
Transition elements - chemical properties
- Less reactive than Group 1 metals, show no clear trend in reactivity
- Most form coloured compounds
- Most form ions w/ different charges
- Have variable oxidation states, so can form more than one compound w/ another element
- Most form complex ions (coordination)
Transition elements - uses
- Many elements and compounds act as catalysts
- Construction of structures (iron) eg. bridges, buildings
- Making jewellery (gold, silver, platinum)
- Many used in making alloys
- Conductors of heat and electricity
Period 3 - trends from left to right
- Proton number and no. of valence electrons increase by one
- Elements go from metal to non-metal - silicon (Group 4) is a metalloid
- MP generally decreases from metals to non-metals
- Electronegativity increases
- Atomic radius decreases
- Aluminium oxide is amphoteric (reacts w/ both acids ad alkalis to form salts)
Why do metals usually have high melting points?
A large amount of heat energy is required to break up the metallic lattice because of their strong metallic bonds and the large number of bonds to be broken
Why are metals malleable and ductile?
The layers of ions can slide easily without breaking the metallic bond, because the electrons are free to move
