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H He
Little Belly Boy Come Near Oreo For Nutrition
Naughty Man And Silly People Should Consume A lot of
Kentucky Combo
GROUP 1 ELEMENTS:
Group 1 elements are alkaline,
Call them as Alkali metals.
Physical properties of group 1 elements
soft metals
silvery and shiny surfaces
low melting and boiling points
good conductors of heat and electricity
low density
When down the group 1….1. Hardness
2. Atomic size the number of atomic shell ↑
3. melting point and boiling point atomic size ↑ distance between the nucleus and the valance electron shell ↑ metallic bond between atoms ↓
4. Density Size ↑ mass more than increase in volume atoms are closer
Element Radius M.p B.p HardnessDensity Electro-
positivity
Li
Na
K
Rb
Cs
Fr
decrease increase
Chemical propertiesR
eact
ivit
y in
crea
se
Down the group
xx
x
x
x
3 P
3 e
3 P
2 e
3 +
2 -
1 +
Duplet (stable)
Li - 1e → Li+
x
xx
xxx
x
xxxx
xx
xxx
x
xxxx
11 P
11 e 11 P
10 e
11 +
10 -
Na - 1e → Na+
Octet (stable)
1 +
K - 1e → K+
Electropositivity
Increase(↑) down the group.
The tendency to donate electrons to form positive ions
x
xx
xxx
x
xxxx
x
x
Li Na
x
Down the group 1, Reactivity ↑
Atomic size ↑
The 1 valence electron become far from the nucleus.
The force of attraction of nucleus on the valence ↓
The single electron becomes easier to be release.
Reactivity ↑
Li < Na < K < Rb < Cs < Fr
3 reactions in group 1
With Oxygen
With water
With halogens
Reaction with oxygen
Reaction with oxygenAlkali metals + oxygen alkali metal oxides
Ex:
4 Li(s) + O2(g) 2Li2O(s)
metal reaction Phenolphthalein indicator
LiBurn with a red flame.
Turns pink
NaBurn with a brightyellow flame.
Turns pink
K Burn violently with a
very bright purplish flame.
Turns pink
Reactivity
↑down the group
Reaction with water
Reaction with waterAlkali metals + water alkaline metals hydroxide + hydrogen gas
Ex:
2Na(s) + 2H2O(l) 2NaOH(aq) + H2(g)
metal
reaction Phenolphthalein indicator
Li Move slowly on the water surface. Turns pink
Na Move at a fast speed on water
surface with a “hissing” sound, burn
with yellow flame.
Turns pink
K Move very fast speed and burn
with a purple flame.
Turns pink
Reactivity
↑down the group
Reaction with Halogen
Chlorine gas
Reaction with Halogen
Alkali metals + halide alkali metals halide
Ex:
2K(s) + Cl2(g) 2KCl(s)
metal reaction product
Li Burn slowly with a
reddish flame.
White solid is obtained
Na Burn brightly with a
yellowish flame.
White solid is obtained
K Burn very brightly with purplish flame.
White solid is obtained
Reactivity
↑down the group
Safety Precautions Alkali metals are highly reactive to water and air.
Kept under non-reactive oil (eg. Paraffin oil)
Never handle with your fingers.
Summary:
Physical
• Shiny and silvery surface
• conductors of heat and electricity
• Hardness
• Atomic size
• Mp
• Bp
• density
Chemical
• Electropositivity
• Reactivity:
• Reaction with oxygen
• Reaction with water
• Reaction with chlorine