Periodic Table Grp Properties

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


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 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)


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


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 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


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


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)


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


changes down changes down the groupthe group

more reactive melting point

decreases density

increases


propertiespropertieschanges changes down the down the groupgroup

more dense


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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Periodic Table Grp Properties

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