Metals Flashcards
define metallic bonds
strong electrostatic forces of attraction between metal cations and sea of delocalised valence electrons
list all 8 properties of metals
- shiny appearance
- solid state @ rtp
- high density
- strong + tough
- ductile (stretch) + malleable (bend)
- high mp & bp
- good conductor of electricity
- good conductor of heat
why do metals have high mp & bp
due to strong electrostatic forces of attraction (between metal cations and sea of delocalised electrons)
why are metals good heat & electricity conductors
due to presence of mobile electrons even when solid
what are some metal exceptions to 1. solid state at rtp & 2. high mp + bp
- mercury
- mercury + alkali metals
define alloy
a mixture of a metal w/ one or a few other elements
why are alloys used instead of pure metals (3)
- in pure metals, layers of atoms with same sizes can slide over each other easily
- in alloys, layers of atoms cannot slide over each other easily bc layers of atoms of alloying elements with different sizes disrupt the orderly arrangement of the metal atoms
- pure metals too malleable & hv less resistance to corrosion
list reactivity series
please - potassium
send - sodium
cats - calcium”
monkeys - magnesium
and - aluminium^
cute - carbon
zebras - zinc
into - iron
large - lead^
heavy - hydrogen”
cages - copper
securely - silver
guarded - gold
“ - non-metal
^ - special metal that reacts diff
what does potassium sodium and calcium have in common (reaction)
- explode in steam; not safe to carry out
- react explosively with acids
what does potassium sodium calcium magnesium and aluminium have in common (reaction)
reacts with cold water to form metal hydroxide + h2
* aluminium + magnesium reacts slowly
what does magnesium aluminium zinc and iron have in common (reaction)
- reacts w/ steam to form metal oxide + h2
- reacts w/ acids to form salt + hydrogen
how is lead diff from copper silver and gold (reaction)
reacts w/ acids
rest do not
what does lead copper silver and gold have in common (reaction)
no observable reaction 4 cold water/steam
how is potassium sodium calcium magnesium and aluminium extracted
extracted by electrolysis
how is zinc iron lead copper and silver extracted
extracted by reduction w/ carbon or hydrogen
* zinc cannot reduce from zinc oxide with hydrogen
how is gold extracted
found naturally; else only need simple heating
list reaction speeds of potassium sodium calcium magnesium and aluminium w/ cold water
- potassium - very violently
- sodium - violently
- calcium - readily
- magnesium - very slowly
- aluminium - very slowly
list reaction speeds of magnesium aluminium zinc iron (and lead) w/ steam
- magnesium - violently
- aluminium - readily
- zinc - readily
- iron - slowly
- (lead - nil)
list reaction speeds of potassium sodium calcium magnesium aluminium zinc iron and lead w/ acid
- potassium - explosive rxn
- sodium - explosive rxn
- calcium - vigorously
- magnesium - rapidly
- aluminium - rapidly
- zinc - moderately fast
- iron - slowly
- lead - slowly
why alkali metals (grp 1 metals) so explosive in cold water
heat produced during rxn causes h2 gas to catch fire and explode
why does lead stop reacting with acid after a while
insol. layer of lead (ii) chloride PbCl2 formed arnd lead metal
why does aluminium react slower/does not react at all at the start with water/acid
has a layer of non-porous aluminium oxide Al2O3 on surface, prevent water/acid from coming into direct contact with aluminium
why is carbon used more frequently by manufactorers instead of hydrogen
cheaper, more effective as reducing agent
why does h2 need to keep passing through the set-up for reduction of metal oxide by h2 until the tube is cool
to prevent re-oxidation of the metals when reacting w/ o2 in the air
