SC13 Flashcards
(21 cards)
What is a transition metal?
- transition metals are a collection of elements in the centre of the periodic table between group 2 and 3
List transition metals
Ti Titanium
V Vanadium
Cr Chromium
Mn Managanese
Fe Iron
Co Cobalt
Ni Nickel
CU Copper
Zn Zinc
Rb Rhubidium
Pd Palladium
Ag Silver
Ir Iridium
Pt Platinum
Au Gold
Hg Mercury
W Tungsten
typical physical properties of transition metals
1) Typically a hugh melting point
2) Typically have a high density
What is a catalyst
A substance which speeds up a chemical reaction but itself remains unchanged voth chemically and in mass
Typical chemical properties of transition metals
3) Typically form coloured products
Copper(II) Carbonate is green
Copper(II) Hydroxiee is blue
Iron(III) oxide is red brown
Iron(III) Hydroxide is orange vrown
4) typically metals and their compounds show catalytic activity such as iron catalyst in haber process
5) form ions with a variable of charges
Fe2+ and Fe3+, Cu1+ and Cu2+
Compare Transition and Alkali Metals
1) Group 1 Metals form ions with a +1 charge, while transition metals form ions with variable charges
2) Transition metals are much harder stronger and denser than Alkali metald which are soft and light
3) Transition metals have higher Boiling points
4) Transition metals are much less reactive than group 1 which react more quickly especially in water
Some transition metald react slwoly or not at all(platinum)
List several uses of transition metals
Iron
-is malleable and ductile so can be used in bridges ships cars and buildings
-has catalytic activity so is used in haber process
copper
-ductile and good electricsl conductor so used in electrical wiring
silver
-shiny so used as reflective coating for mirrors in infrared telescoped
titanium haa high strength resistant to corrosion lighter and thinner better for heat transfer and doesnt react so is used in fighter aurcrsft artificial hip joints and pipes in nuclesr power plants
Transition metals and their alloys
Iron makes strel
Zinc and copper make brass
What is electroplating?
-when a surface of a metal is coated with a thin layer of another metal
-makes use of electrolysis
eg) jewellery, gold/silver electroplated onto other cheaper metals such as nickel or copper
Examples of electroplating
Chromium in bathroom fittings as it is resistant to corrosion stopping air and water from reaching the metal below
Silver plating used in electricsl components as it increases electrical conductivity
zinc or cadium electroplating for steel volts to reduce corrosion
What are the rules of electroplating?
The anode sgould he from the same metal as the electroplating metal
The object you want to electroplate is the cathode
the electrolyte myst xontain ions of the electroplating metal and the electrolyte must be sollubule
describe electroplating in a copper silver ring
anode is silver metal
cathode is copper ring
electrolyte is silver nitrate solution
1) silver atoms in anode lose electrons becoming silver ions
- silver ions go into the electrolyte
- silver ions go in the electrolyte are attracted to the negatively charged copper ring(cathode)
4) silver ions gain electrons and are lect as silveratoms
What is an alloy?
-a mixture of a metal with atleast on other element
-such ad steel(made of iron carbon and other elements), bronze, brass, solder, amalgam
describe bronze
Bronze an alloy of copper and tin its highly ductile, resists corrosion and a good electrical conductor, ised in sculptors, bells, medals
describe brass
made of copper and zinc does not tarnish so is used as door knobd, buttons and in instruments
describe solder
made of zinc and lead has a low melting point do uded in electronics to attach componentd to circuit boards
describe pure gold and its alloys
-pure gold is actually quite soft
-yellow gold is an alloy of gold and copper and silver
-white gold is an alloy of nickel platinum or palladium with gold
What is steel?
-an alloy of iron and other elements usch as nickel carbon and chromium
-stronger than pute iron and can be used in almost anything from sauce pans to suspension bridges
Why are alloys stronger than pure metals? use iron as eg
atoms in pure iron are arranged densely packed layers. these layers can slide each other making pure iron very soft material
the wtom of other elements are of different sizes. when elements are added to iron, their atoms distort the regular structure of the iron atom
it is more difficult for these layers of iton in steel to slide of iron atoms in steel to slide over eachother and so, this alloy is stronger than iron
Describe the different steel and theirnuzes
Mild Steel
-up to 0.25% carbon
-both malleable and ductile
-however rusts when exposed to oxygen and water
-3 times denser than aluminium(heaver)
-used in nails car bodies ships and buildings
High Catbon Steel
-0.6 -1.2> carbon, sometimes contains small amounts of manganese to make it more malleable
-harder and more resistant to wear than mild steel but more brittle
-used in cutting tools, masonry and nails
stainless steel
-made of chromium and nickel
-resistant to corrision, chrommium forms an oxide layer which protects iron from being oxidised
-used in kitchen sinks sauce pane knives forks and gardening tools
What is shape memory Alloy?
-a type of smart material made from metals able to return to its original dhape after being deformed
Nitinol
-a type of shape memory alloy made of nickel and aluminium
-used to make a pair of gladses thst remembers its dhape and does not break when crushed
-nitinol has also been used to hold badly broken bones in place while they heal
