Nitrogen Family Properties (PDF)

# Nitrogen family ## General properties 1. **Order of covalent radius**: N < P < As < Sb < Bi - There is only a small increase in covalent radius from As to Bi due to the presence of completely filled *d* and/or *f* orbitals in heavier members. 2. **Order of ionization energy**: N > P > As > Sb > Bi (same order for 1E1, IE2, and IE3) 3. **Order of density**: N Sb < Bi - As > Sb > Bi > P 5. **Order of boiling point**: N < P < As < Sb < Bi 6. **Metallic character increases down the group**. 7. **Physical state**: Nitrogen is a diatomic gas, while all others are solids. - Nitrogen due to its small size can satisfy its trivalency by triple bond formation. Mol.wt is less, so it exists in the gas phase. P cannot form stable triple bonds due to its size and forms tetra atomic molecules to satisfy its trivalency. Hence, its mol.wt increases, and it exists in a solid state. ## ⑧ Allotropy - Except for 'N', all other members show allotropy. - **Phosphorus** - **Ores** - Bone ash/phosphorite: Ca3(PO4)2 - Chlorapatite: 3 Ca3(PO4)2.CaCl2 - Fluorapatite: 3 Ca3(PO4)2.CaF2 - **Preparation and properties** - Ca3(PO4)2 + C + SiO2 → P4 + CaSiO3 + CO2 (white) - Δ at 473K at high P - Δ at 573K in inert atmosphere for several days. - β-black P, red P, λ-black P ## White P - It is a translucent, white, waxy, poisonous, garlic-smelling solid. - It is highly reactive due to its angle strain and is thermodynamically least stable allotrope of phosphorus. - It is insoluble in water, but it is soluble in organic solvents like CS2/Benzene/CHCl3, etc. - It reacts with atmospheric air to emit light i.e., it shows chemiluminescence called as phosphorous. ## Red P - It is a less reactive, odourless, non-poisonous solid. - It doesn't show phosphorescence as P4. - It is used in the match industry as P4S3. - It is insoluble in both water and CS2 ## Black P - It is the thermodynamically most stable allotrope of 'P'. - It is insoluble in water and other organic solvents like CS2/CHCl3 /Benzene etc. - It is inert and has a layer structure. ## Scence **Gx:**: P4 + O2 → P4O10 + heat - White cloud - Heat - Glows in dark ## Note - **Thermodynamic stability**: Black > Red > White - **S4H- value**: s4H- = -ve - Δ Hf = 0 - Due to its reactivity and abundance, it was chosen. - **NaOH**: White P → P4H3 ↑ - Red P → No P4H3 evolved - **Conduction of electricity**: - White P → Don't conduct electricity - Red P → Don't conduct electricity - Black P → Semiconductor # ChemINFO-1.19 ## Daily Self-Study Dosage for mastering Chemistry **Comparison between White and Red phosphorus** | Property | White phosphorus | Red phosphorous | |----------|--------------------|--------------------| | (1) Physical state | Soft waxy solid | Brittle powder | | (2) Colour | White when pure Attains, yellow colour on standing | Red | | (3) Odour | Garlic | Odourless | | (4) Solubility in H2O | Insoluble | Insoluble | | (5) Solubility in CS2 | Soluable | Insoluable | | (6) Physiological Action | Poisonous | Non poisonous | | (7) Chemical activity | Very Active | Less active | | (8) Stability | Unstable | Stable | | (9) Phosphorescence | Glows in dark | Does not glow in dark | | (10) Reaction with NaOH | Evolves phosphine | No action | | (11) Molecular Formula | P4 | Complex polymer | **Note**: **Order of stability**: Black phosphorus > R.P. > W.P. **Order of Reactivity**: B.P. < R.P. < W.P. **Order of density**: B.P > R.P > W.P **Order of m.p**: B.P > R.P > W.P ## Chemical properties 1. **Electronic Configuration**: ns2 np3 2. **Oxidation States** - **Common oxid" States** = -3, +3 and +5. - Bi3+ > Sb3+>As3+ } stability. - "N" exhibit a large no. of oxidation States. - **Intermediate oxidation states tend to get disproportionation.** - HNO2 → HNO3 + NO↑ + H2O (acid/alkaline) - H3PO3 → H3PO4 + PH3↑ (medium acid/alkaline medium) - H3PO2 → H3PO4 + PH3↑ - **But +5 state of As, Sb and Bi are increasingly stable toward disproportionation.** ## 3 Rxn with O2 - Group-15 elements generally form 2 types of oxides. - E2O3 and E2O5 ( *All acidic*) - E2O5 → E2O3 ( acidity order) - N → N2O → P4O6 → P4O8 → P4O10 - P → ***formed due to π bond formation tendency*** - As → As4O6 → As4O8 → As4O10 - Sb → Sb4O6 → Sb4O8 → Sb4O10 - Bi → Bi2O3 - **Acidity ↑** - Oxides in +3 oxidation state act as reducing agents and their reducing action decreases from N to Bi, as +3 oxidation stability increases. - Oxides in +5 oxidation state act as oxidising agents. - Bi+5 → Strong oxidising agent. ## 4 Reaction with H2 - Elements of group-15 form EH3 type of hydrides where E = N/P/As/Sb/Bi - These are colourless, poisonous gases and poisonous nature increases from NH3 to BiH3. - **Order of BA:** NH3 > PH3 > AsH3 > SbH3 > BiH3 - **Order of b.p: ** BiH3 > SbH3 > NH3 > AsH3 > PH3 ~90° (*Dragosrule*) - **Gomp:** NH3 > SbH3 > AsH3 > PH3 (*most volatile*) ## pppy Order of Basicity: NH3 > PH3 > AsH3 > SbH3 ## Pr) Order of stability: NH3 >PH3 > AsH3 > SbH3 ## Order of reducing action: BiH3 > SbH3 > AsH3 > PH3 > NH3 ## viy Order of covalent character: NH3 < PH3 < AsH3 < SbH3 < BiH3 ## 5 Reaction Towards X2 - **Ex3 and Ex5** - **Trihalide & Pentahalide** - "N" donot form pentahalides due to non-availability of *d* -orbitals. - All are explosives - **NF3, Ne2, NBr3 , NI3.** - **NF3 Stable, Ne2 explosive, NBr3, NI3** exist as NBr3.6NH3, NI3.6NH3 - *Unstable ammoniates* ## Note: - for a given element of 15th group: **Fluoride > chloride > Bromide > iodide** - (*order of stability*) - **P > PBr3 > PCl3 > PF3** (*Reducing nature of halides*) - **Bi**: BiF3, BiCl3 , BiBr3, BiI3 (*ionic & Covalent*) - **Element**: **EX3 & EX5** - N NF3, NCl3, NBr3, NI3 ---------- --- - P PF3, PCl3, PBr3, PI3, PF5 PCl5 PBr5 - As AsF3, AsCl3, AsBr3, AsI3 AsF5, AsCl5 - Sb SbF3, SbCl3, SbBr3, SbI3 SbF5, SbCl5 - Bi BiF3, BiCl3, BiBr3, BiI3 ***BiI5***

Nitrogen Family Properties (PDF)

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