Groups in the Periodic Table Flashcards
What are typical properties of transition metals?
Hard, strong, shiny, malleable, good conductors of heat and electricity, high melting points, high densities, catalysts, form colourful compounds
How does metallic bonding work?
Positive ions are surrounded by delocalised electrons and form strong bonds
Why do metals conduct electricity?
They have delocalised electrons that can carry a charge
Why do metals have high melting points?
There are strong bonds between negative electrons and positive ions
Why are alloys stronger than pure metals?
Metals have layers of atoms in sheets that can slide over each other easily, so it can bend. Adding another element that has atoms of different sizes disrupts these sheets, so they cannot slide
What are limits of atomic models?
Some are only two dimensional, rather than three in real life
Ions and particles are very large, while in real life they would be small, with lots of empty space between them
What are the alkali metals and their symbols?
Lithium - Li Sodium - Na Potassium - K Rubidium - Rb Caesium - Cs Francium - Fr
Why are alkali metals more reactive as you go down the group?
There are more electron shells, so the outermost electron is further from the nucleus, so the attraction force is weaker, so it can be lost more easily
What are properties of group 1 metals?
Soft, low melting and boiling points, float on water - low densities, very reactive with water, form an alkali in water
How do alkali metals react with water?
They float, move around and fizz. Over time they disappeared as they turned into hydroxide and let off hydrogen gas.
Potassium produced a purple flame
Rubidium and caesium explode
What is the reaction between alkali metals and water?
e.g. Lithium + water –> lithium hydroxide + hydrogen
2Li + 2H2O –> 2LiOH + H2
What is the test for hydrogen?
Hold a test tube over it and hold a lit splint over it. If it makes a squeaky pop sound, hydrogen gas is present
Why are halogens found in pairs?
They need to form a covalent bond to have a full outer shell. This is called diatomic, as opposed to monotomic
What are the halogens and their symbols?
Fluorine - F Chlorine - Cl Bromine - Br Iodine - I Astatine - At
What are the states and colours of the halogens?
Fluorine - gas - pale yellow Chlorine - gas - green Bromine - liquid - red Iodine - solid - grey, purple vapour Astatine - solid - black
What is the test for chlorine gas?
Chlorine turns damp blue litmus paper red, then bleach it white
How do halogens react with metals?
They react vigorously with some to form salts called metal halides
Sodium + chlorine –> sodium chloride
2Na + Cl2 –> 2NaCl
How do halogens react with hydrogen?
They react to form soluble hydrogen halides
Hydrogen + chlorine –> hydrogen chloride
H2 + Cl2 –> 2HCl
Why do halogens get less reactive as you go down?
There is less of a force to attract an electron to the nucleus, so it gets harder to attract the extra electron to fill the outer shell
Why are halogen displacement reactions redox reactions? Give an example
The halogens lose electrons (oxidation)
Halide ions gain electrons (reduction)
Cl2 + 2KBr –> Br2 + 2KCl
Oxidised Reduced
What are the noble gases and their symbols?
Helium - He Neon - Ne Argon - Ar Krypton - Kr Xenon - Xe Radon - Rn
Why are noble gases inert?
They have a full outer shell, so they don’t easily give up or gain electrons
What are properties of noble gases?
Colourless, gases at room temperature, inert, non-flammable, hard to observe
What are uses of noble gases?
Providing an inert atmosphere, light bulbs and welding (to stop metals from burning or being oxidised), and airships and balloons (low densities and inert)
What are patterns in the noble gases?
Boiling points and melting points increase as you go down
Density increases as you go down the group
