ChapteChapter r 1616
ChapteChapter r 1616
Group PropertiesGroup Properties
1 outer shell electron
form ions with a charge of +1; form ionic compounds of similar formulas
very reactive metals; metals are kept under oil to prevent corrosion by air and water
shiny, silvery solids
soft and have low densities (can be cut with a knife!)
low melting points
react with water to give alkaline solutions, producing metal hydroxide and hydrogen gas
group I elements - the alkali metals
propertiesproperties
changes down group I elementschanges down group I elements densities increase
melting points decrease
more reactive
NameName SymbolSymbol Density (g/cmDensity (g/cm33)) Melting Point (Melting Point (°°C)C)
lithium Li 0.53 180
sodium Na 0.97 98
potassium K 0.86 64
rubidium Rb 1.5 39
caesium Cs 1.9 29
group I elements - the alkali metals
Alkali MetalsAlkali Metals ObservationObservation Equation for ReactionEquation for Reaction
lithium fast reaction 2Li + 2H2O 2LiOH + H2
sodium
very fast reaction; sometimes sodium
catches fire and explodes
2Na + 2H2O 2NaOH + H2
potassium explosion 2K + 2H2O 2KOH + H2
reactions of group I elements with water: reactions of group I elements with water:
reaction with waterreaction with water
group I elements - the alkali metals
group VII elements - the halogens
7 outer shell electrons ions with a charge of -1 very reactive non-metals diatomic molecules low melting and boiling points a more reactive halogen will displace a less reactive
halogen from an aqueous solution of its ions
Cl2(aq) + 2KI(aq) I2(aq) + 2KCl(aq)
propertiesproperties
react vigorously with metals to form ionic salts
2Na(s) + Cl2(g) 2NaCl(s)
changes down group VII elementschanges down group VII elements melting and boiling points increase
elements become darker in colour
less reactive
change from gas to solid
changes in physical properties of group VII elements
gaseous chlorine
liquid bromin
e
solid iodine
group VII elements - the halogens
HalogensHalogens Formula of Formula of MoleculeMolecule
Melting Melting Point (Point (°°C)C)
Boiling Boiling Point (Point (°°C)C)
Physical Physical State at State at Room Room
ConditionCondition
ColourColour
fluorine F2 -220 -188 gaspale
yellow
chlorine Cl2 -101 -35 gasyellow-green
bromine Br2 -7 59 liquidReddish brown
iodine I2 114 184 solid black
group VII elements - the halogens
group 0 elements – the noble gases
monatomic, colourless gases
full valence shells; no wish to form bonds with other atoms
unreactive
low melting and boiling points
monatomic, colourless gases
full valence shells; no wish to form bonds with other atoms
unreactive
low melting and boiling points
Noble GasesNoble Gases PropertiesProperties UsesUses
helium very low density; unreactiveballoons and
modern airships
neonunreactive; hot wire will not
burn in the gasadvertising strip
lights
argon provide an inert atmospherelight bulbs and steel
production
propertiesproperties
the transition elements
propertiesproperties high densities and melting points
not very reactive
strong and hard metals
variable valency and oxidation states in compounds
Transition MetalsTransition Metals Other MetalsOther Metals
MetalMetal Density Density (g/cm(g/cm33))
Melting Melting Point (Point (°°C)C) MetalMetal Density Density
(g/cm(g/cm33))Melting Melting
Point (Point (°°C)C)
chromium 7.2 1890 sodium 0.97 98
iron 7.9 1535 magnesium 1.7 650
nickel 8.9 1453 aluminium 2.7 660
copper 8.9 1083 calcium 1.5 850
the transition elements
propertiesproperties coloured compounds
formed; solutions of ions in water are also coloured
elements and their compounds are good catalysts
solutions of transition metal ions from left: manganate(VII), dichromate(VI), copper(II),
nickel(II)
the transition elements
uses of transition elements and their compounds:
Transition Elements/ Transition Elements/ CompoundsCompounds UsesUses
tungsten filaments for light bulbs
iron mixed with a little carbon (alloy – steel)
nails, ships
copper, iron and cobalt bright colours in porcelain
ironas a catalyst in Haber Process for the
manufacturing of ammonia
vanadium(V) oxideas a catalyst in Contact Process for the manufacturing of sulphuric acid
nickelas a catalyst to manufacture
margarine from vegetable oils
halogenshalogens
group propertiesgroup properties
alkali metalsalkali metals noble gasesnoble gases
atoms have 1 outer shell electron
form M+ ions conduct electricity have low melting points are soft have low densities very reactive metals react with water to form
alkali MOH and H2 gas
transition elementstransition elements
conduct electricity have high melting and boiling points have high densities have variable valency form coloured compounds are often good catalysts form strong alloys
atoms have 8 outer shell
electrons unreactive gases form monatomic
molecules
atoms have 7 outer shell electrons form X- ions do not conduct electricity have low melting and boiling points form diatomic molecules X2 reactive non-metals form salts with metals each displaces other halogens below from their salts in water
propertiesproperties
changes down changes down the groupthe group
more reactive melting point
decreases density
increases
propertiesproperties
propertiespropertieschanges changes down the down the groupgroup
more dense
propertiesproperties
changes down changes down the groupthe group
darker in colour melting and boiling points increase from gas to solid less reactive
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