Chemical properties of p block elements .

p block elements

1. Chemical Properties O f P-block E lements MOOMNA FAHEEM

2. P Block elements The elements in which valence electron are enter in p sub shell are known as p block elements. The p block elements is the region of periodic table that include group 13 to group 18 and does not include He .

3. GROUP 13 ELEMENTS (ICOSAGENS) The chemical properties of group 13 elements reflect the increasingly metallic character down the group. The elements of group 13 are : Boron Aluminum Gallium Indium Thallium

4. Boron : Boron is chemically unreactive except at high temperatures . Finally divided boron burn in air to form oxides and nitride : 2B +2O 2 → 2B 2 O 3 (oxides) 2B + N 2 → 2BN (nitride) Accordingly in halogen boron form trihalides 2B + 2X 3 → 2BX 3 Boron does not react with acid like HCl and HF but powdered boron reacts with concentrated HNO3 ( nitric acid ) .

5. … Reactivity towards alkali : the boron is unreactive when come in contact with alkali at moderate temperature.. B + NaOH → NO REACTION

6. Aluminum Aluminum undergo following reactions : Reactivity toward air : A luminum burns in air if it is in powdered form . Other wise , aluminum form a thin layer of oxide which make it unreactive to other substances. Amorphous aluminum when reacted with air by providing heat form Al2O3 . 2Al +30 2 → 2Al 2 O 3 Reaction with chlorine : Aluminum reacts with chlorine by passing dry chlorine over a heated aluminum foil . 2Al +3Cl 2 → 2AlCl 3

7. Group 14 Elements : ( crystalogens ) Group 14 elements are : Carbon Silicon Germanium Tin lead

8. Carbon : Carbon under go following reactions : Reaction with air : carbon remains unreactive with air at ordinary temperature . A strong heating carbon is converted into co and co 2 . 2C + O 2 → 2CO 2C + 2O 2 → 2CO 2 Formation of carbides : when carbon is heated in the presence of CaO ,calcium carbide is obtained. CaO + 3C →CaC 2 + CO

9. … Reaction with water : Water has no reaction on carbon but steam reacts when passed over a red hot carbon to form water gas .(co and h 2 ) . C + H 2 O → CO + H 2 Reaction with hydrogen : when hydrogen is pass through carbon heated at the temperature of electric arc , acetylene is formed . 2C + H 2 → C 2 H 2

10. Silicon : Silicon undergo following reactions : R eaction with air : Silicon burns in air on heating to form silicon dioxide . Si + O 2 → SiO 2 Reaction with alkali : Silicon get dissolved in alkalies liberating hydrogen . Si +2NaOH + H 2 O →Na 2 SiO 3 + 2H 2

11. … Reaction with halogens : Silicon reacts with fluorine only directly . Chlorine , bromine and iodine do not directly react with it . Si + 2F 2 → SiF 4 Reaction with water : Silicon does not reacts with water at ordinary temperature but react with steam to give oxide . Si + 2H 2 O → SiO 2 + 2H 2

12. Group 15 Elements : ( Pnictogens ) The elements of group 15 are : Nitrogen Phosphorus Arsenic Antimony Bismuth Moscovium

13. Nitrogen : Nitrogen undergo following reactions : Reaction with hydrogen : N itrogen reacts with H 2 at about 600 C under pressure in the presence of catalyst . N2 + 3H2 → 2NH3 ( +141 KJ ∕ mol ). R eaction with oxygen : Nitrogen reacts with oxygen only in the presence of electric spark . Reaction of nitrogen and oxygen also take place in the atmosphere at the time of lightning produce by the charged clouds . N2 + O2 → 2NO ( -180 KJ ∕ mol ).

14. … Reaction with metals : Metals such as Mg , Li and Al , etc reacts with nitrogen to form nitrides . N 2 + 3Mg → Mg 3 N 2 N 2 + 2Al → 2AlN N 2 + 6Li → 2Li 3 N Reaction with calcium carbide When calcium, carbide is he ated at about 1000 C in presence of N2, Calcium Cyanamide is formed. CaC 2 +N 2 →CaCN 2 +C

15. Phosphorus Phosphorus undergo following reaction Reaction with oxygen : White phosphorus react with oxygen at 35-45 C but Red phosphorus doesn’t react with O2 below 240 C P4+3O2 →P4O6 P4+5O2→P4O10 Reaction with Alkalis : Alkalis react with white phosphorus to liberate phosphine gas. Red phosphorus doesn’t react under these conditions. P 4 +3O 2 +3NaOH→PH 3 +3NaH 2 PO 2

16. … Reaction with Halogens Phosphorus react with Halogens to form PX 3 . F 2 react more quickly. P 4 +6X 2 → 4PX 3 Reaction with Hydrogen Phosphorus doesn’t react with H 2 in elementary state .

17. Group 16 Element ( Chalcogens ) The element of group 16 are . Oxygen Sulfur Selenium Tellurium polonium

18. Oxygen Oxygen is highly reactive non metallic element. As it readily formed compound with almost all other elements. Reaction with Hydrogen Oxygen react with hydrogen to form water (H20) and hydrogen peroxide (H2O2) . 2H 2 + O 2 → 2H 2 H 2 + O 2 → H 2 O 2 Reaction with Group1 element Oxygen react with group1 element readily . 4Li+O 2 →2Li 2 O 3 4Na+O 2 → 2Na2O With other alkali metals M+O 2 →MO 2

19. … Reaction with group2 Elements Alkaline earth metal also react with oxygen, though not as rapidly as group1 metals. These reaction also required heat . 2M+O2→2MO Where M Represent Be , Mg , Ca , Sr , Ba and Ra.

20. Group 7 Elements ( Halogens) The element of 7 group are Fluorine Chlorine Bromine Iodine astatine

21. Chemical reaction of Halogen The most important reaction of halogens are Reaction with Hydrogen All halogen react with halogen under different condition to give Hydrogen Halides. H 2 +X 2 →2HX ( X = HALOGENS ) Reaction with Oxygen Halogen formed number of oxides. Fluorine react with oxygen at high voltage discharge. Other in cold and hot state to form different salts of oxyacid.

22. … Cl 2 +2NaOH→NaCl + NaClO + H 2 O Br 2 +2NaOH→NaBr+ NaBrO + H 2 O I 2 +NaOH→NaI+HIO Reaction with H 2 S Halogen oxidize H 2 S to liberate free sulfur . X 2 +H 2 S→2HX+S

23. Group 8 Elements ( Noble Gases) The group 8 elements are Helium Neon Argon Krypton Xenon Radon

24. … Noble Gases have low chemical reactivity. The full valence electron shells of these atoms make noble gases extremely stable and unlikely to form chemical bonds because they have little tendency to gain or lose electrons.