one electron in outer shell

found in group 1

similar physical and chemical properties

readily lose the outer shell electron to form positive ions with a +1 charge

down the group, more dense but the trend is not perfect because K is less dense than Na.

• Soft metals with silvery colour.

• Good thermal/electrical conductors

• Li -> K - less dense than water,

• Rb&Cs –more dense

• Kept in oil in order to avoid oxidation

• Melting points decreases down the group

• Ionic/atomic radii increases down the group

• Density increases down the group

• Ionization energy,IE decreases down the group

•Adhering properties increased down the group

Each atom in this group consist of one valence
electron in the s orbital

down a group

• Increase in size
• Increase in shielding effect
• Decrease in Ionization Energy (IE) - Low ionization energy

exist as ionic compunds
eg: NaCl

The separation of free ions in gas phaseneed energy so /_\Hlatt (+ve)
M+X-(s) -> M+(g) + X-(g)

crystal structure: Body Centered Cubic (BCC)

exist as covalent compounds
eg: Na2

soluble in water

normally white in colour except KMnO4-purple

very high melting points

towards free ions involves released energy -> Esolv./hyd (-ve)
M+(g) + X-(g) -> M+(aq) + X-(aq)

Li- crimson
Na- yellow
K- red- lilac/violet
Rb- red
Cs- blue

the smaller the size of the ions, the bigger the ionic charge -> the stronger the bond between ions and solvent. So, more energy is released.

towards free ions involves released energy -> Esolv./hyd (-ve)
M+(g) + X-(g) -> M+(aq) + X-(aq)

The separation of free ions in gas phase

• need energy so /_\Hlatt (+ve)
  M+X-(s) -> M+(g) + X-(g)

ion size: Li+ < Na+ < K+ < Rb+ < Cs

Borax, at Nevada USA

K cannot be obtained by electrolysis of the KCl due to

• the melting point of KCl (776 °C) is higher than K metal (762 °C)
• K metal dissolves in molten salt
• Discharge potential for K+ and Ca2+ is similar, if the molten used KCl-CaCl2

Reduction of molten chloride with Na vapour
MCl(l) + Na(g) M(l) + NaCl(l) e.g. Potassium
KCl(l) + Na(g) NaCl(s) + K(l)

LiAlH4 - reducing agents for organic compounds – produce H.

Lithium complex oxide, LiNbO3 – use in mobile communication devices – due to nonlinear optical and acousto-optical effect

as coolant in reactor nuclear

NaCl – flavouring food, road de-icing

Cs – alloy with Al and Ba is used in photoelectric cell

4M + O2 -> 2M2O (M= Na, K)

M2O + H2O -> 2MOH

2MOH + CO2 + nH2O -> M2CO3.nH2O

M+2H2O->2MOH+ H2 (M=Li < Na < K < Rb <.Cs)
increasing alkalinity

metal is extremely reactive

• Very Electropositive, forming positive ions
  (Cations) -> act as Electron Donor

monoxide (M2O)

1. Directly from metal and H2 gas->form saline hydride
2. Reaction between group IA oxides in a flow of H2 gas
   M2O(s) + H2(g) -> MH(s) + MOH(s)
   

m/p: LiH=700oC, NaH/KH~400oC

React violently with water

Reaction with alcohol -> alcoholate

Reaction with liquid ammonia -> amide

Reaction with oxygen -> oxide

As reducing agent : produce H2

as source of hydrogen gas

as bleaching agent

to get rid of CO2 and produce O2 in a closed area

electrolysis

• Electrolyte: Brine (Concentrated NaCl)
• Anode: Carbon (Graphite),
• Cathode : Mercury

bleaching agent

Solvay process

Colourless and transparent solid

Exist as hydrated salt

A precursor for GLASS manufacturing industries

In manufacture of sodium silicate/water glass

Manufacturing of soap and detergent

As hard water softener

Manufacturing of borax

fire extinguisher

gastric medicine

buffer in wine product & water treatment

buffer in low pH liquid detergent

• Deliquescent solid
• Used in making other nitrates, fertilizers and explosives

• Naturally occurs as mineral saltpetre
• Slightly soluble in cold water but very soluble in hot water
• Used in manufacturing explosives, fireworks, matches and fertilizers

Trend of /\Hf
• F- to I- : /\ Hf becomes less negative due to increase radius of the anion and , /_\Hlatt becomes less negative

down the group,

• /_\Hf for Cl-, Br-, I- becomes
  more negative
• /\Hf for F- becomes less negative due to increase in radius of M+ , /\Hlatt also
  decrease (less negative)

stable- high electro+ve charge

Li2CO3 – decompose upon heating
Li2CO3->Li2O + CO2
Other carbonate : do not decompose

Exhibit covalent character in its bonding

Form normal oxide, Li2O

LiH is stable to heating to 900oC, Other hydride decompose above 400oC

carbonates easily decomposed to CO2 and an oxide when heated.

sulphates and carbonates salts insoluble in water

Formed carbides and nitrides on direct heating in C and N2

Halides soluble in various organic solvents

nitrates decomposed to an oxide, nitrogen dioxide and oxygen
when heated