10/12/2017
e NJV Government Higher Secondary School lies on a sprawling multi-acre campus on main MA Jinnah Road, in the heart of Karachi’s historic Saddar district. This historic monument was established by Sir Bartle Frere in 1855 and is the first public school in Sindh. This school was named after Rao Narayan Jagannath Vaidya who had worked for many years with zeal and self-sacrifice for the advancement of education in Sindh, NJV was a premier school that attracted the brightest minds from all over the province. Akhuwat adopted the school in 2015 with a mission to restore NJV to its former glory and preserve its heritage.
The secure campus contains one main building, a primary building, a student dormitory, staff housing, along with various peripheral buildings such as garages, a canteen, post office and a guardhouse. The 3-story main building has full internet coverage and houses 8 laboratories, 3 IT rooms, multiple auditoriums, and over 40 classrooms to deliver world-class education to our students.
New construction and works are ongoing; slated projects include a gymnasium, new IT rooms, a state of the art library, cafeteria, a renovated primary school building, art department and arts college.
04/04/2017
HYDROGEN
Position of hydrogen in periodic table
Position of an element in periodic table depends upon its electronic configuration and properties. Hydrogen resembles the elements of group I-A, IV-A and VII-A in some respects. Properties of hydrogen do not completely match any one of the above-mentioned groups. That is why position of hydrogen is still undecided.
In the coming lines we will discuss why hydrogen can not be placed in a particular group in the periodic table.
Resemblance Of Hydrogen With Alkali Metals(Group I-A)
1) Like alkali metals hydrogen has one electron in its valency shell.
Explanation
H (Z=1): K1
Li (Z=3): K2, L1
Na (Z=11): K2, L8, M1
(2) Valance shell electronic configuration of hydrogen and alkali metal is same.
Explanation
H (Z=1): 1S1
Na (Z=11): 1S2,2S2,2P6,3S1
3) Both hydrogen an alkali metals are good reducing agents.
4) Like alkali metals hydrogen can also form halides.
Explanation:
Hydrogen:
HCl, HI.
I-A:
NaCl, KBr.
5) Halides of alkali metals and hydrogen ionized in similar way in aqueous solution.
Explanation:
HCl (aq) è H+(aq) + Cl-(aq)
NaCl(aq) è Na+(aq) + Cl-(aq)
6) Like alkali metals hydrogen can also form compounds with non-metals.
Explanation:
I-A:
Na2S
Hydrogen:
H2S
[S and Cl are non-metals]
DIFFERENCES :-
1) Hydrogen is a non-metal where as elements of I-A are metals.
2) Hydrogen can form both covalent and ionic compounds. But alkali metals only form ionic compounds.
3) Hydrogen cannot lose its valence electron.
4) Hydrogen is a gas at room temperature but alkali metals are solids.
5) Unlike Na+ or K+ hydrogen ion (H+) is unstable in water.
Explanation:
H+ + H2O è H3O+
6) I.P. of hydrogen is very high as compared to alkali metals.
Explanation
I.P. of hydrogen is 313 Kcal per mole.
I.P. of alkali metals max. is 147 Kcal per mole.
Resemblance of Hydrogen with Carbon Family (IV-A)
1) Valance shell of hydrogen is half-filled like the elements of group IV-A.
Explanation:
H (Z=1) : Capacity of K-Shell =2 , no. of electrons = 1 , % = 50%
C(z=6) : Capacity of L-Shell = 8 , no. of electrons = 4 , % = 50%
2) I.P. and E.A. of hydrogen and carbon are comparable.
3) E.N. of H and Carbon family are almost similar. [H = 2.1, C = 2.5 , Si= 2.4]
Explanation
DIFFERENCES
1) Carbon is tetravalent but Hydrogen is a mono-valent.
2) Hydrogen is a gas at room temperature but elements of group IV-A are solids.
3) Boiling and melting points of hydrogen is very less than that of the elements of group IV-A.
Resemblance Of Hydrogen With Halogens
1) Both Hydrogen and Halogens require one electron to complete their valence shell.
2) Both hydrogen and Halogens are non-metals(Except iodine which has partial metallic character).
3) Both hydrogen and Halogens acts as negative ions when combined with metals.
4) Their molecules are diatomic.
5) Like Halogens, hydrogen can also form both ionic and covalent bond.
Explanation
Hydrogen:
NaH (ionic),
CH4 (Covalent)
Halogens:
NaCl (ionic), HCl
6) Both H and Halogens form compound with metals and non-metals.
Explanation
Hydrogen :H2S [S=non-metal]
Halogens : HCl [H = non-metal]
DIFFERENCES
1) Hydrogen has one electron in valence shell while Halogens has seven electrons.
2) Electronic configuration of H = 1S1,
Valence shell electronic configuration of Halogens = nS2, nS5
3) Unlike X- ion, H- ion is unstable in water and reacts in the following manner.
Explanation
H- + H2O èH2+ OH-
UNIQUE ATOMIC STRUCTURE OF HYDROGEN:
Hydrogen is the only element which has no neutron in its nucleus.
Conclusion
Due to above reasons it is clear that hydrogen cannot be placed in any one of the above mentioned groups.
25/10/2016
Suna h bht sasta h lahu us jahan ka.,
Ek basti h Jise log kehte h..😵😵
Another black day in
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Admit card college say mil reh hain aa kar laye lye
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Admit card aa chukye hai college main kiya
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jis jis nain apna practical gernal check nh karawaya wo is week main karwa laye wrna apni galti ka wo khud zumeedar ho ga by admin
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FOCUS on learning one skill that can help you achieve your most important goal. Then from there, gradually scale it up to achieve more.
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This video lecture from Mathematical Induction and Binomial Theorem (F.Sc. first year Mathematics) covers: detailed discussion on the concept and use of binomial theorem. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional a…