Excellent studentsđź‘‘đź‘‘:
🔥Increasings or Decreasing Order🔥
đź”´ 01. Melting point=
Li > Na > K > Rb > Cs
đź”´ 02. Colour of the flame=
Li-Red, Na-Golden, K-Violet, Rb-Red, Cs-Blue, Ca-Brick red, Sr-Blood red, Ba-Apple green
đź”´ 03. Stability of hydrides =
LiH > NaH > KH > RbH> CsH
đź”´ 04. Basic nature of hydroxides=
LIOH < NaOH < KOH < RbOH < CsOH
đź”´ 05. Hydration energy=
Li> Na > K> Rb > Cs
đź”´ 06. Reducing character=
Li > Cs > Rb > K > Na
đź”´ 07. Stability of +3 oxidation state=
B> Al > Ga > In > T1
đź”´ 08. Stability of +1 oxidation state= Ga < In < TI
đź”´ 09. Basic nature of the oxides and hydroxides=
B< Al< Ga < In < TI
đź”´ 10. Relative strength of Lewis acid= BF3 < BCl3 < BBr3 < BI3
đź”´ 11. Ionisation energy=
B> Al <Ga > In <TI
đź”´ 12. Reactivity=
C<Si< Ge < Sn <Pb
đź”´ 13. Metallic character=
C< Si < Ge < Sn < Pb
đź”´ 14. Acidic character of the oxides=
Co2 > SiO2 > Ge02 > SnO2 > PbO2
đź”´ 15. Reducing nature of hydrides=
CH4 < SiH4 < GeH4 < SnH4 < PbH4
đź”´ 16. Thermal stability of tetrahalides=
CCl4> SiCl4> GeCl4> SnCl4 > PbCl4
đź”´ 17. Oxidising character of M+4 species=
GeCl4 < SnCl4 < PbCl4
đź”´ 18. Ease of hydrolysis of tetrahalides=
SiCl4 < GeCl4 < SnCl4 < PbCI4
đź”´ 19. Acidic strength of trioxides=
N203 > P2O3 > As2O3
đź”´ 20. Acidic strength of pentoxides=
N2O2 > P2O2> As202 > Sb2O2 > Bi‌202
đź”´ 21. Acidic strength of oxides of nitrogen=
N2O < NO <N2O3 <N2O4 < N2O5
đź”´ 22. Basic nature/ bond angle/ thermal stability and dipole moment of hydrides=
NH3 > PH3 > AsH3 > SbH3 > BiH3
đź”´ 23. Stability of trihalides of nitrogen=
NF3 > NCl3 > NBr3
đź”´ 24.Lewis base strength=
NF3 <NCl3 <NBr3 < NI3
đź”´ 25. Ease of hydrolysis of trichlorides=
NCl3 > PCI3 > AsCl3 > SbCl3 > BiCl3
đź”´ 26. Lewis acid strength of trihalides of P, As, and Sb=
PCl3 > ASCl3 > SbCl3
đź”´ 27. Lewis acid strength among phosphorus trihalides
PF3 > PCl3 > PBr3 > PI3
đź”´ 28. Melting and boiling point of hydrides=
H2O > H2Te > H2Se >H2S
đź”´ 29. Volatility of hydrides=
H2O < H2Te < H2Se < H2S
đź”´ 30. Reducing nature of hydrides=
H2S < H2Se < H2Te
đź”´ 31. Covalent character of hydrides=
H2O < H2S < H2Se < H2Te
đź”´ 32. The acidic character of oxides (elements in the same oxidation state)=
SO2 > SeO2 > TeO2 > PoO2
SO3 > SeO3 > TeO3
đź”´ 33. Acidic character of oxide of a particular element (e.g. S)=
SO < SO2 < SO3
SO2 > TeO2 > SeO2 > PoO2
đź”´ 34. Bond energy of halogens=
Cl2 > Br2 > F2 > I2
đź”´ 35. Solubility of halogen in water =
F2 > Cl2 > Br2 > I2
đź”´ 36. Oxidising power=
F2 > Cl2 > Br2 > I2
đź”´ 37. Enthalpy of hydration of X ion=
F- > Cl- > Br- >I-
đź”´ 38. Reactivity of halogens:=
F> Cl> Br > I
đź”´ 39. Ionic character of M-X bond in halides
= M-F > M-Cl > MBr > M-I
đź”´ 40. Reducing character of X ion:=
I- > Br- > Cl- > F-
đź”´ 41. Acidic strength of halogen acids=
HI > HBr > HCI > HF
đź”´ 42. Reducing property of hydrogen halides
= HF < HCL < HBr < HI
đź”´ 43. Oxidising power of oxides of chlorine
= Cl2O > ClO2 > Cl206 > Cl2O7
đź”´ 44. Decreasing ionic size=
02- > F- > Na+ > Mg2+
đź”´ 45. Increasing acidic property=
Na2O3 < MgO < ZnO< P205
đź”´ 46. Increasing bond length=
N2 <02 < F2 < CL2
đź”´ 47. Increasing size=
Ca2+ < Cl- < S2-
đź”´ 48. Increasing acid strength=
HClO < HClO2 < HClO3 < HClO4
đź”´ 49. Increasing oxidation number of iodine=
HI< I2 <ICl <HIO4
đź”´ 50. Increasing thermal stability=
HOCl < HOClO < HOClO2 < HOClO3
✍️Notes on Biotechnology
Steps of recombinant DNA technology
(1) Isolating a useful DNA segment from the donor organism.
(2) Splicing it into a suitable vector under conditions to ensure that each vector receives no more than one DNA fragment.
(3) Producing of multiple copies of his recombinant DNA.
(4) Inserting this altered DNA into a recipient organism.
(5) Screening of the transformed cells.
Vectors:
Vector in genetic engineering is usually a DNA segment used as a carrier for transferring selected DNA into living cells. These are as follows:
(1) Plasmid: Plasmid is extra chromosomal, closed circular double stranded molecules of DNA present in most eukaryotes. All plasmid carry replicons pieces of DNA that have the genetic information required to replicate. Plasmid pBR 322 was one of the first widely used cloning vectors, it contain both ampicillin and tetracycline resistance genes.
(2) Phage: It is constructed from the phage l chromosomes and acts as bacteriophage cloning vectors.
(3) Cosmid: The hybrids between plasmid and the phage l chromosome give rise to cosmid vectors.
(4) Beside all these there are artificial chromosomes like
(i) BACs (Bacterial Artificial chromosomes)
(ii) YACs (Yeast Artificial chromosomes)
(iii) MACs (Mammalian Artificial chromosomes) are very efficient vectors for eukaryotic gene transfers.
Application of recombinant DNA technology:
The technique of recombinant DNA can be employed in the following ways.
(1) It can be used to elucidate molecular events in the biological process such as cellular differentiation and ageing. The same can be used for making gene maps with precision.
(2) In biochemical and pharmaceutical industry, by engineering genes, useful chemical compounds can be produced cheaply and efficiently which is shown in table.
âś…Notes on s-Block Elements:
Physical Properties of Alkali Metals:
âž–These are soft in nature and can be cut with the help of knife except the lithium.
âž–The atoms of alkali metals have the largest size in their respective periods.
âž–The first ionization energy of the alkali metals are the lowest as compared to the elements in the other group.
âž–The alkali metals show +1 oxidation state.
âž–The alkali metals have low values of reduction potential (as shown in table-I) and therefore have a strong tendency to lose electrons and act as good reducing agents.
âž–The melting and boiling points of alkali metals are very low because the intermetallic bonds in them are quite weak.
Hydroxides of Alkali Metals:
a)All the alkali metals, their oxides, peroxides and superoxides readily dissolve in water to produce corresponding hydroxides which are strong alkalies.
➖2Na + 2H2O → 2NaOH + H2
âž–Na2O + 2H2O 2NaOH
➖Na2O2 + 2H2O → 2NaOH + H2O2
➖2KO2 + 2H2O → 2KOH + H2O2 + O2
b) The basic strength of these hydroxides increases as we move down the group Li to Cs.
c) All these hydroxides are highly soluble in water and thermally stable except lithium hydroxide.
d) Alkali metals hydroxides being strongly basic react with all acids forming salts.
➖NaOH + HCI → NacI + H2O
➖2NaOH + H2 SO4 → Na2SO4 + 2H2O
Halides of Alkali metals:
➖M2O + 2HX → 2MX + H2O
➖MOH + HX → MX + H2O
➖M2CO3 + 2HX → 2MX + CO2 + H2O (M = Li, Na, K, Rb or Cs)
(X = F, Cl, Br or I)
âž–ll the alkali metals form ionic (electrovalent) compounds.
âž–The alkali metals are good conductors of heat and electricity.
âž–Alkali metals (except Li) exhibit photoelectric effect
âž–The alkali metals and their salts impart a characteristic colour to flame.
âś…Notes on s-Block Elements:
Physical Properties of Alkali Metals:
âž–These are soft in nature and can be cut with the help of knife except the lithium.
âž–The atoms of alkali metals have the largest size in their respective periods.
âž–The first ionization energy of the alkali metals are the lowest as compared to the elements in the other group.
âž–The alkali metals show +1 oxidation state.
âž–The alkali metals have low values of reduction potential (as shown in table-I) and therefore have a strong tendency to lose electrons and act as good reducing agents.
âž–The melting and boiling points of alkali metals are very low because the intermetallic bonds in them are quite weak.
Hydroxides of Alkali Metals:
a)All the alkali metals, their oxides, peroxides and superoxides readily dissolve in water to produce corresponding hydroxides which are strong alkalies.
➖2Na + 2H2O → 2NaOH + H2
âž–Na2O + 2H2O 2NaOH
➖Na2O2 + 2H2O → 2NaOH + H2O2
➖2KO2 + 2H2O → 2KOH + H2O2 + O2
b) The basic strength of these hydroxides increases as we move down the group Li to Cs.
c) All these hydroxides are highly soluble in water and thermally stable except lithium hydroxide.
d) Alkali metals hydroxides being strongly basic react with all acids forming salts.
➖NaOH + HCI → NacI + H2O
➖2NaOH + H2 SO4 → Na2SO4 + 2H2O
Halides of Alkali metals:
➖M2O + 2HX → 2MX + H2O
➖MOH + HX → MX + H2O
➖M2CO3 + 2HX → 2MX + CO2 + H2O (M = Li, Na, K, Rb or Cs)
(X = F, Cl, Br or I)
âž–ll the alkali metals form ionic (electrovalent) compounds.
âž–The alkali metals are good conductors of heat and electricity.
âž–Alkali metals (except Li) exhibit photoelectric effect
âž–The alkali metals and their salts impart a characteristic colour to flame.
