lithium

Question 1

What is electronegativity?

Answer 1

The ability of an atom in a molecule to attract electrons to itself

Question 2

Explain the trends in the periodicity of alkali metals?

Answer 2

the atomic radius and the ionic radius increase down the group
the electronegativity and ionisation energy decreases down the group

Question 3

What is the source/occurrence of alkali metals?

Answer 3

• Salts - not in elemental states

Rb, Li, Cs have small natural abundance

Question 4

How does Extraction take place?

Answer 4

Electrolysis starting from NaCl (KCl, LiCl)

Question 5

what is the characteristics of lithium metals

Answer 5

very reactive
soft
storage under oil or oxygen free atmosphere

alkali oxide: - heating in excess of air
alkali chloride:- prepared by reacting metals with cl2 and good aqueous solubility
alkali carbonate - li2co3 sparingly soluable

Question 6

uses of lithium?

Answer 6

• Industrial use: batteries, glass manufacture, metal alloys
  Clinical use: manic depression and bipolar disorder

Question 7

What is a diagonal relationship?

Answer 7

Adjacent elements of the second and third periods have similar properties
mg2+ and li
have similar ionic radius - competition for binding sites in protein
have similar solubility
hydrated compounds

Question 8

what is the clinical use of lithium

Answer 8

• Orally taken as Li2CO3
  
  • Max dose per day 30mmol
  • Can be irritating to GI tract
  • Treatment is monitored 12h after
  • Very narrow therapeutic index
  • Magnesium balance in blood and urine is altered
  • Lithium is not soluble in lipids and therefore does not pass plasma membrane
  • Exchange into cells by
    ○ Lithium sodium counter transport
    ○ Anion exchange
    ○ Unrelated transport molecules

Question 9

Where is lithium distributed in the body?

Answer 9

• Uniformly in body tissues, blood plasma with external cell
  Mostly distributed to bone and kidney

Question 10

Why does bones have the highest concentration of lithium?

Answer 10

Bones act as sink for lithium

Body try’s to get rid of it by storing it safely

Question 11

Why is lithium used as a mood stabiliser?

Answer 11

They work by inhibiting key enzyme in bipolar disorder - active site for carbamazepine
Li is very toxic - narrow therapeutic window

Question 12

what are some adverse effects caused by lithium?

Answer 12

• tremor
  weight gain
  -memory problems
  -extreme doses can cause dirahoea and nausea
  diabetes inspidus
  decreased thyroid levels
  kidney functions has to be closely measured

Question 13

What is the interaction with lithium and NSAID?

Answer 13

• 60% increase in blood lithium concentration
  
  • This is because
    ○ It causes reduced clearance of lithium through kidney - lithium poisoning possible
    Sodium depletion make lithium toxicity worse, therefore concurrent use of diuretics is hazardous

Question 14

What are some lithium drugs on the market?

Answer 14

camcolit
liskonum
praidel
lithium citrate