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Syllabus

^{–l}respectively. The number of valence electrons is:

(A) 3 (B) 5 (C) 4 (D) 2

Q.1. Which of the following is not a Dobereiner triad ?

(a) Cl, Br, I

(b) Ca, Sr, Ba

(c) Li, Na, K

(d) Fe, Co, Ni

(l) Cu will precipitate out

(2) Iron will precipitate

(3) Cu and Fe will precipitate

(4) No reaction will take place

I believe it should be helium!?

Option(2). How?

Q16. Given

Li(g) $\to $Li

^{+}(g)$\frac{1}{2}{\mathrm{F}}_{2}\left(\mathrm{g}\right)\to \mathrm{F}\left(\mathrm{g}\right)$

F(g) + e¯$\to $F¯(g)

Li+(g) $\to $F¯(g) $\to $LiF(s)

Li (s) + $\frac{1}{2}$F2(g) $\to $Li F(s)

520

77

(Electron gain enthalpy)

–1047

–617

Based on data provided, the value of electron gain enthalpy of fluorine would be :

(1) – 300 kJ mol

^{–1}(2) – 328 kJ mol^{–1}(3) – 350 kJ mol^{–1}(4) – 228 kJ mol^{–1}explain electonegativity?

what is sheilding effect?

Reducing means gain of electrons, if IE will increase ; it means atom want electrons, not give, right?

So it is directly proportional?!

Ionization Enthalpy is defined as the amount of energy required to remove an atom's electron (can be valence or consecutive) ..... this definition doesn't sound so complex. The definition of Electron Gain Enthalpy - it is the amount of energy required to add an electron. But, what is Electron Affinity ? One book says it is the negative of electron gain enthalpy. Then, there is some thermodynamic rule saying negative value of electron gain enthalpy indicates that energy has to be supplied and positive value indicates energy is released. My question is how can electron gain enthalpy have both negative and positive values but ionisation enthalpy doesn't have. Also please explain what the differnece between affinity and gain enthalpy is.Thanks in advance ....

Proof the diagonal relationship between Li and Mg

Be and Al

B and Si

a. In the sixth period, after filling of 6p orbitals, the next electron ( i.e. 57th) enters the 5d-orbital against aufbau principal and there after filling of seven 4f- orbitals starts with cerium (Z=58) and end up with lutetium (Z=71). Explain the anomalous behaviour.

Ans: option 4.

How?

Q.55. For which of the elements of different groups, the change in nonpolar covalent radii is maximum ?

(1) Groups 1 and 2

(2) Groups 14 and 15

(3) Groups 16 and 17

(4) Groups 17 and 18

Explain in detail About The position of "Hydrogen" and "Helium" in Modern Periodic Table ?

Pls help asap.

Ans: option 1.

How?

Is it boron or carbon?

of the periodic table. Write down the general outer electronic configuration of the ten elements from La to Hg together using orbital notation method.

periodic table

s d p f

With reason

BaO and SrO

Please explain..

(1) CO

_{2}< SiO_{2}< SnO_{2}< PbO_{2}: increasing oxidising power(2) B < C < O < N : increasing first ionisation enthalpy

(3) NH

_{3}< PH_{3}< AsH_{3}< SbH_{3}: increasing basic strength(4) HF < HCl < HBr < HI : increasing acid strength

text notes downlod

Q. Which of the following represent the correct order of acidic strength?

$a.CaO{H}_{2}OCuOC{O}_{2}\phantom{\rule{0ex}{0ex}}b.{H}_{2}OCuOCaOC{O}_{2}\phantom{\rule{0ex}{0ex}}c.S{O}_{2}{P}_{2}{O}_{3}Si{O}_{2}A{l}_{2}{O}_{3}\phantom{\rule{0ex}{0ex}}d.{P}_{2}{O}_{3}S{O}_{2}Si{O}_{2}A{l}_{2}{O}_{3}$

Please clear my doubt!

how we kan calculate sigma ?

I am confused.

Ans : 4 acidic compounds.

Show how?

Q2. Select total number of acidic compounds out of given below.

CsOH, OC(OH)

_{2}, SO_{2}(OH)_{2}, Sr(OH)_{2}, Ca(OH)_{2}, Ba(OH)_{2}, BrOH, NaOH, O_{2}NOHHow? Please explain each and every point.:

13. Carefully read the following four statements related to Slater's rule and identify them as True (T) or False (F).

I - Z

_{eff}value for the valence s-electron increases more rapidly, in moving left to right in a period, in 's' and 'p' block elements compared to d-block elements.II - Z

_{eff}value for the outermost s-orbital of f-block elements, becomes constant irrespective of the number of (n-2)f - electrons and this contradicts f- contraction. This fact can be said to be a drawback of Slater's rule.III -The Slater's rule does not take into account, the relative penetrating power of s and p-orbitals.

IV - In general, for the d-block elements of 3d-series, the value of Z

_{eff}increases by 0.65 unit per element.(A) TFTF (B) TFFF (C) TTTF (D) FTTF

Ans: option 4.

Ans: option (B).

How barium has higher I.E. than potassium?

Q.19. Decreasing ionization potential for K, Ca & Ba is

(A) Ba > K > Ca

(B) Ca > Ba > K

(C) K > Ba > Ca

(D) K > Ca > Ba

Ans: option(4). How?

h. In which case compounds of Cr show maximum radius

i. K

_{2}CrO_{7}ii. CrO

_{2}Cl_{2}iii. Cr

_{2}(SO_{4})_{3}iv. CrCl

_{2}Multiple match.

Ans key: (C)- S , (D)- Q,R.

How?

1]glyoxal[2]BHC

Ans: D.

How? I got something else...

Na2co3

Nahco3

Caco3

Ans : option b.

How?

Q43. Which of the following formula has involved all the energy terms used to calculated $\u2206{\mathrm{H}}_{\mathrm{\u0192}}^{\xb0}\mathrm{of}{\mathrm{Na}}_{2}{\mathrm{O}}_{\left(\mathrm{s}\right)}$ ($\u2206$H

_{sb}: Sublimation energy ; LE_{1}: First ionisation energy; LE_{2}: Second ionisation energy ; B.D.E, ; Bond dissosiation energy ; E. G.E_{1}: First electron gain enthalpy ; E.G.E_{2}: Second electron gain enthalpy ; U : Lattice energy)(A) + 2$\u2206$H

_{sb}+ LE_{1}+ LE_{2}+ $\frac{\mathrm{B}.\mathrm{D}.\mathrm{E}}{2}+\mathrm{E}.\mathrm{G}.{\mathrm{E}}_{1}+\mathrm{E}.\mathrm{G}.{\mathrm{E}}_{2}+\mathrm{U}$(B) + 2$\u2206$H

_{sb}+2LE_{1}+ $\frac{\mathrm{B}.\mathrm{D}.\mathrm{E}}{2}+\mathrm{E}.\mathrm{G}.{\mathrm{E}}_{1}+\mathrm{E}.\mathrm{G}.{\mathrm{E}}_{2}+\mathrm{U}$(C) + 2$\u2206$H

_{sb}+2LE_{1}+ $+\frac{\mathrm{B}.\mathrm{D}.\mathrm{E}}{2}+2\mathrm{E}.\mathrm{G}.{\mathrm{E}}_{1}+\mathrm{U}$(D) + 2$\u2206$H

_{sb}+ LE_{1}+ $\frac{\mathrm{B}.\mathrm{D}.\mathrm{E}}{2}+\mathrm{E}.\mathrm{G}.{\mathrm{E}}_{1}+\mathrm{E}.\mathrm{G}.{\mathrm{E}}_{2}+\mathrm{U}$Tomorrow's my test!