1.   if the edge lenght of unit cell of NaCl is 600pm and ionic radius of Cl ion is 190pm, then the ionic radius of Na ion is:

i. 310

ii. 110

iii. 220

iv. none

 

2.in a solid AB having NaCl structure 'A' atoms occupy the  corners of unit cell. if all the face centered atoms along one of the axes are removed, then resultant stoichiometry is:

AB₂

A₂B

A₄B₃

A₃B₄

 

PLZ  ans these questions step wise .rates assured !!!!

the temp above  which micelle formation takes place is kraft temp.

 

note:  above it

hello all!!!

in the solid state we have the 7lattices, right??? all of u must have devised some way to memorize it. i want to share my way.plz let me know whether u liked it or not. if u have some more methods do share with all !!!

 

the seven lattices are cubic, tetragonal, orthorombic, hexagonal, rhombohedral, monoclinic and triclinic. first, remeber this CT OH RMT. Keep this in ur mind and  u will be able to do it.

 

C-CUBIC

T-tetragonal

O-orthorombic

H-hexagonal,

R-rhombohedral

M-monoclinic

T-triclinic

 

NOW, THE NEXT STEP IS TO REMEMBER THE DIMENSIONS.

first we have,

a=b=c

a=bc

abc

a=bc

a=b=c

abc

ab c

 

 

can u notice a pattern? if not, i will tell u.

first all three are equal

 then we put unequal sign b/w b and c

 then all the three bcum unequal.

then again c is not equal to b.

then all three are equal agian 

 all three are unequal

all three are unequal.

( so basically there is a shift in no. of = and not equal to sign.)

 

LETS MOVE ON TO THE ANGLES.

a=b=y=90

a=b=y=90

a=b=y=90

a=b=90, y=120

a=b=y90

a=y=90, b 120

aby90

 

now here do u notice a pattern???

three times all the three angles are equal to each other and 90.

then we have a and b equal to each other and 90 but y is 120.

all the angles are eual to each other but not 90.

then now, a and y are equal to each other and 90 but b is NOT 120

then neither is equal to each other and 90..

 

EXAMPLES:

for cubic- take the first two letters of cubic u have Cu which is one example.u can remember NaCl as  it is salt and when salt comes into ur mind, u can associate it with sugar crystals which are sort of cubic in shape.

 

for tetragonal, remember white Tin and TiO₂    (T in both).

for orthorhombic, simple one rhombic sulphur and BaSO₄ ( Both compunds can be related by sulphur)

for hexagonal, we already know graphite and ZnO( ZnO can be remembered by that xa sound similar to za)

rhombohedral - other name for it is trigonal. tri means three. so we have CaCO₃

and relate that with cinnabar( C frm CaCO3 and Cinnabar).

then monoclinic is simple, we have monoclinic sulphur as one example and Na₂SO₄.10H₂O.

last but not the least we have triclinic. see TRI meaning 3. hence example IS H₃BO₃ .

 SO, IN SHORT.........

systems                axial angles       distances     examples

CUBIC                  a=b=y=90             a=b=c       Cu, NaCl

TETRAGONAL      a=b=y=90             a=bc       White Tin, TiO2

ORTHORHOMBIC  a=b=y=90             abc       Rhombic Sulphur BaSO₄

HEXAGONAL         a=b=90, y=120       a=bc        graphite and ZnO

RHOMBO

HEDRAL               a=b=ynot=90         a=b=c        CaCO₃,cinnabar                                                                                                                                                     .

MONOCLINIC       a=y=90, b 120  abc     monoclinic S                                     

TRICLINIC.             aby90               abc   H₃BO₃

 

hope u all found it useful. plz let me know.

when u say timetable, do u mean time management or the syllabus.

 

i, personally feel that u shud  pay attention to ur xi as it gives u a foundation for xii. i enjoyed too much in xi tthat i have to work extra hard now. for the time being just concentrate on ur xi so that next year u wont feel burdened. all the best!!!!!

 

ah,yes, keep a routiine timetable for ur studies and etch it in ur mind that during studies u r just going to study and not think abt anything else.

remember, quality of studies is more important than quantity of studies ie it does not matter how much time u study but how u make use of the available time.

a positively charged particle is projected frm east to west near equator of erth. give direction of magnetic lorentz force acting on this particle?

 

 

im asking a lot of questions but i have no other option. got to submit my HW and so i have so many doubts. sorry!!!

arrang in increasing order of magnitude:

escape velocity of electron frm earth's gravity,  velocity of free electron in earths atmosphere at room temp, velocity of light, typical drift velocity of electron in metal.

             CH₃          

              |

CH₃CH₂-C(Cl)-CH₂-CONHCH₂CH_3.

 

http://www.cem.msu.edu/~reusch/VirtualText/nomen1.htm.

 

its quite nice. many practice problems too.

hope u all like it.

it is the phenomenon of bending of light around corners of an obstacle(or aperture). the light thus penetrates into the geometrical shadow of obstacle and deviates form its linear path.

 

for more info, check this

 

hope it was useful!!!!

actually the pattern of iitjee has changed. if ur basics are strong and ur fundas are clear then u will be able to pass the exam wid flying colours. just give as many mock tests as u can and see if u r able to finish it within the time limit.

students feel that the level is high. but it is not so..

 

so all the best!!!!!!