Modern Periodic Table :- Gp 15 elements :- CBSE Class XII

1. GROUP-15GROUP-15
ELEMENTSELEMENTS

2. 7.1.1 Occurrence
Molecular nitrogen comprises 78% by volume of the atmosphere. In the earth’s crust, it
occurs as sodium nitrate, NaNO (called Chile saltpetre) and potassium nitrate (Indian
saltpetre). It is found in the form of proteins in plants and animals. Phosphorus occurs in
minerals of the apatite family, which are the main
components of phosphate rocks. Phosphorus is an essential constituent of animal and
plant matter. It is present in bones as well as in living cells. Phosphoproteins are present
in milk and eggs. Arsenic, antimony and bismuth are found mainly as sulphide minerals.
INTRODUCTIONINTRODUCTION

3. ATOMIC AND PHYSICAL PROPERTIES OF GROUP
15 ELEMENTS

4.  Electronegativity (the atom's ability of attracting electrons) increases up the group.
 Ionization Energy (the amount of energy required to remove an electron from the atom in
it's gaseous phase) increases up the group.
 Atomic Radii (the radius of the atom) increases down the group.
 Electron Affinity (ability of the atom to accept an electron) increases going up the group.
 Melting Point (amount of energy required to break bonds to change a solid phase substance
to a liquid phase) increases going down the group.
 Boiling Point (amount of energy required to break bonds to change a liquid phase substance
to a gas) increases going down the group.
 Metallic Character (how metallic the atom is) increases going down the group.
 Electronic Configuration. The valence shell electronic configuration of these elements is
ns2np3. The s orbital in these elements is completely filled and p orbitals are half-filled,
making their electronic configuration extra stable.
 Atomic and Ionic Radii. Covalent and ionic (in a particular state) radii increase in size down
the group. There is a considerable increase in covalent radius from N to P. However, from As
to Bi only a small increase in covalent radius is observed. This is due to the presence of
completely filled d and/or f orbitals in heavier members.
TRENDS IN PROPERTIES

5. SOME IMPORTANT GROUP
– 15 ELEMENTS
NITROGENNITROGEN
ANDAND
PHOSPHORUSPHOSPHORUS
NITROGENNITROGEN
ANDAND
PHOSPHORUSPHOSPHORUS

6. Nitrogen is a chemical element with symbol N and atomic number 7. Elemental nitrogen is a colourless, odourless,Nitrogen is a chemical element with symbol N and atomic number 7. Elemental nitrogen is a colourless, odourless,
tasteless, and mostly inert diatomic gas at Std. conditions constituting 78.09% by volume of Earth’s Atmosphere. Thetasteless, and mostly inert diatomic gas at Std. conditions constituting 78.09% by volume of Earth’s Atmosphere. The
element nitrogen was discovered as a separable component of air, by Scottish physician Daniel Rutherford , in 1772..element nitrogen was discovered as a separable component of air, by Scottish physician Daniel Rutherford , in 1772..
Nitrogen occurs in all organisms, primarily in amino acids and also in the nucleic acids. The human body containsNitrogen occurs in all organisms, primarily in amino acids and also in the nucleic acids. The human body contains
about 3% by weight of nitrogen, the fourth most abundant element in the body after oxygen, carbon, and hydrogen.about 3% by weight of nitrogen, the fourth most abundant element in the body after oxygen, carbon, and hydrogen.
ProductionProduction
Nitrogen gas is an industrial gas produced by the fractional distillation of liquid air , or by mechanical means usingNitrogen gas is an industrial gas produced by the fractional distillation of liquid air , or by mechanical means using
gaseous air (i.e., pressurized reverse osmosis membrane. In a chemical laboratory it is prepared by treating angaseous air (i.e., pressurized reverse osmosis membrane. In a chemical laboratory it is prepared by treating an
aqueous solution of ammonium chloride with sodium nitrite NH4Cl(aq) + NaNO2(aq) → N2(g) + NaCl(aq) + 2aqueous solution of ammonium chloride with sodium nitrite NH4Cl(aq) + NaNO2(aq) → N2(g) + NaCl(aq) + 2
H2O (l)H2O (l)
Small amounts of impurities NO and HNO3 are also formed in this reaction. The impurities can be removed bySmall amounts of impurities NO and HNO3 are also formed in this reaction. The impurities can be removed by
passing the gas through aqueous sulfuric acid containing potassium dichromate Very pure nitrogen can be preparedpassing the gas through aqueous sulfuric acid containing potassium dichromate Very pure nitrogen can be prepared
by the thermal decomposition of barium azide 2 NaN3 → 2 Na + 3 N2by the thermal decomposition of barium azide 2 NaN3 → 2 Na + 3 N2
PropertiesProperties
Nitrogen is a non-metal with an electronegativity of 3.04. It has five electrons in its outer shell and is,Nitrogen is a non-metal with an electronegativity of 3.04. It has five electrons in its outer shell and is,
therefore, trivalent in most compounds. The triple bond in molecular nitrogen (N2) is one of the strongest. Thetherefore, trivalent in most compounds. The triple bond in molecular nitrogen (N2) is one of the strongest. The
resulting difficulty of converting N2 into other compounds, and the ease (and associated high energy release) ofresulting difficulty of converting N2 into other compounds, and the ease (and associated high energy release) of
converting nitrogen compounds into elemental N2, have dominated the role of nitrogen in both nature and humanconverting nitrogen compounds into elemental N2, have dominated the role of nitrogen in both nature and human
economic activities.economic activities.
At atmospheric pressure molecular nitrogen condenses (liquefies) at 77 K (−195.79 °C) and freezes at 63 KAt atmospheric pressure molecular nitrogen condenses (liquefies) at 77 K (−195.79 °C) and freezes at 63 K
(−210.01 °C) into the beta hexagonal close-packed crystal allotropic form. Below 35.4 K (−237.6 °C) nitrogen assumes(−210.01 °C) into the beta hexagonal close-packed crystal allotropic form. Below 35.4 K (−237.6 °C) nitrogen assumes
the cubic crystal allotropic form (called the alpha phase). Liquid nitrogen a fluid resembling water in appearance, butthe cubic crystal allotropic form (called the alpha phase). Liquid nitrogen a fluid resembling water in appearance, but
with 80.8% of the density (the density of liquid nitrogen at its boiling point is 0.808 g/mL), is a common cryogen.with 80.8% of the density (the density of liquid nitrogen at its boiling point is 0.808 g/mL), is a common cryogen.
NITROGEN

7. REACTIONSREACTIONS
Structure of dinitrogen, NStructure of dinitrogen, N22 in general, nitrogen is unreactive at standard temperature and pressure. Nin general, nitrogen is unreactive at standard temperature and pressure. N22 reacts reacts
spontaneously with fewre agents, being resilient to acids and bases as well as oxidants and most reductants.spontaneously with fewre agents, being resilient to acids and bases as well as oxidants and most reductants.
When nitrogen reacts spontaneously with a reagent, the net transformation is often called nitrogen fixation.When nitrogen reacts spontaneously with a reagent, the net transformation is often called nitrogen fixation.
Nitrogen reacts with elemental lithium. Lithium burns in an atmosphere of NNitrogen reacts with elemental lithium. Lithium burns in an atmosphere of N22 to give lithium nitride. 6 LI to give lithium nitride. 6 LI
+ N+ N22 → 2 LI → 2 LI33N magnesium also burns in nitrogen, forming magnesium nitride. 3 MG + NN magnesium also burns in nitrogen, forming magnesium nitride. 3 MG + N22 → MG → MG33NN22
COMPOUNDSCOMPOUNDS
TThe main neutral hydride of nitrogen is ammonia (NH3), although hydrazine (N2H4) is also commonlyhe main neutral hydride of nitrogen is ammonia (NH3), although hydrazine (N2H4) is also commonly
used. ammonia is more basic than water by 6 orders of magnitude. in solution ammonia formsused. ammonia is more basic than water by 6 orders of magnitude. in solution ammonia forms
the ammonium ion (NH4the ammonium ion (NH4++
). liquid ammonia (boiling point 240 K) IS amphiprotic (displaying). liquid ammonia (boiling point 240 K) IS amphiprotic (displaying
either brønsted-lowry acidic or basic character) and forms ammonium . singly, doubly, triply and quadruplyeither brønsted-lowry acidic or basic character) and forms ammonium . singly, doubly, triply and quadruply
substituted alkyl compounds of ammonia are called amines (four substitutions, to form commercially andsubstituted alkyl compounds of ammonia are called amines (four substitutions, to form commercially and
biologically important quaternary amines, results in a positively charged nitrogen, and thus a water-soluble,biologically important quaternary amines, results in a positively charged nitrogen, and thus a water-soluble,
or at least amphiphilic, compound). larger chains, rings and structures of nitrogen hydrides are also known,or at least amphiphilic, compound). larger chains, rings and structures of nitrogen hydrides are also known,
but are generally unstable.but are generally unstable.
the higher oxides dinitrogen trioxide N2O3, dinitrogen tetroxide N2O4 AND dinitrogen pentoxide N2O5,the higher oxides dinitrogen trioxide N2O3, dinitrogen tetroxide N2O4 AND dinitrogen pentoxide N2O5,
are unstable and explosive, a consequence of the chemical stability of N2. nearly every hypergolic rocketare unstable and explosive, a consequence of the chemical stability of N2. nearly every hypergolic rocket
engine uses N2O4 as the oxidizer; their fuels, various forms of hydrazine, are also nitrogen compounds.engine uses N2O4 as the oxidizer; their fuels, various forms of hydrazine, are also nitrogen compounds.
these engines are extensively used on spacecraft such as the space shuttle and those of the Apollothese engines are extensively used on spacecraft such as the space shuttle and those of the Apollo
program because their propellants are liquids at room temperature and ignition occurs on contact withoutprogram because their propellants are liquids at room temperature and ignition occurs on contact without
an ignition system, allowing many precisely controlled burns.an ignition system, allowing many precisely controlled burns.

8. Phosphorus is a nonmetallic chemical element with symbol P and atomic number 15., phosphorus as a mineral
is almost always present in its maximally oxidized state, as inorganic phosphate rocks. Elemental phosphorus
exists in two major forms—white phosphorus and red phosphorus but due to its high reactivity, phosphorus is
never found as a free element on Earth. Forms of phosphorus and their properties
Occurrence
Phosphorus is not found free in nature, but is widely distributed in many minerals, mainly phosphates. Histo
-rically-important but limited commercial sources were organic, such as bone ash and (in 19th
century) guano.
Inorganic phosphate rock, which is partially made of apatite (an impure tri-calcium phosphate mineral), is today
the chief commercial source of this element. About 50 % of the global phosphorus reserves are in the Arab
nations.
Applications
Fertilizer
The dominant application of phosphorus is in fertilizers, which provides phosphate as required for all life and is
often a limiting nutrient for crops. Phosphorus, being an essential plant nutrient, finds its major use as a
constituent of fertilizers for agriculture and farm production in the form of concentrated phosphoric acids, which
can consist of 70% to 75% P2
O5
. Due to the essential nature of phosphorus to living organisms, the low
solubility of natural phosphorus-containing compounds, and the slow natural cycle of phosphorus, the
agricultural industry relies on fertilizers that contain phosphate.
Water softening
Sodium tripolyphosphate made from phosphoric acid is used in laundry detergents in some countries, but
banned for this use in others. It is useful for softening water to enhance the performance of the detergents and
to prevent pipe/boiler tube corrosion
PHOSPHORUS

9. COMPOUNDS OF PHOSPHORUSCOMPOUNDS OF PHOSPHORUS

10. The EndThe End
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