Atomic Size and Electronegativity

Q.

Nitrogen exists as diatomic molecule and phosphorus as $P_4$ why?

Q.

Except nitrogen , all the 15 group element is allotropy?

Q. Calculate the electronegativity of fluorine from the following data:
Bond energy of H-H bond $E_{H-H}=104.2kcalmo{l}^{-1}$
Bond energy of F-F bond$E_{F-F}=36.6kcalmo{l}^{-1}$
Bond energy of H-F bond $E_{H-F}=134.6kcalmo{l}^{-l}$
Electronegativity of Hydrogen $X_H=\mathrm{2.1.}$

1. 3.87
2. 2.76
3. -3.87
4. -2.76

Q. Calculate the electronegativity of chlorine from the given data: bond energy of $Cl-F$ bond $\left(61kcalmo{l}^{-1}\right)$, $F-F$$\left(38kcalmo{l}^{-1}\right)$ and $Cl-Cl$ bond $\left(58kcalmo{l}^{-1}\right)$ and electronegativity of fluorine is $4.0$.

1. $3.22$
2. $3.33$
3. $2.67$
4. $2.33$

Q. Atomic radii of group 15 elements is of the order

1. N>P>As>Bi>Sb
2. N>P>As>Sb>Bi
3. N<P<As<Sb<Bi
4. N<P<As<Sb>Bi

Q.

Which of the following have no unit?
(a) Electronegativity (b) Electron gain enthalpy
(c) Ionlsation enthalpy (d) Metallic character

Q.

Draw diagrams showing the formation of a double bond and a triple bond between carbon atoms in $C_2{H}_4$ and $C_2{H}_2$ molecules.

Q. H – H, X – X and H – X bond energies are 104 K cal/mole, 60 K cal/mole and 101 K cal/mole. Assuming the electronegativity of hydrogen to be 2.1 the electronegativity of unknown element ‘X’ is $(\sqrt{19}=4.36)$

1. 3.5
2. 3
3. 4
4. 2.5

Q. Which pair of elements can from multiple bond with itself and oxygen?

1. $F,N$
2. $N,Cl$
3. $N,P$
4. $N,C$

Q. The species $Ar,K^{+},C{a}^{2+}$ contain the same number of electrons. In which order do their radii increase?

1. $C{a}^{2+}<K^{+}<Ar$
2. $K^{+}<Ar<C{a}^{2+}$
3. $Ar<K^{+}<C{a}^{2+}$
4. $C{a}^{2+}<Ar<K^{+}$

Q. 'X' is the sum of delocalised lone pair and number of nitrogen in melamine. Find the value of X.

Q. Would you expect the hydrides of $N,O$ and $F$ to have lower boiling points than the hydrides of their subsequent group members ? Give reasons.

Q. The unit of length convenient on an atomic scale is known as angstrom and is denoted by A=10^-10m the size of hydrogen atoms is about 0.5 angstrom what is the total atomic volume in m^3 of a mole of hydrogen atom

Q. If the ionic radii of $K^{+}$ and $F^{-}$ are $1.34\stackrel{\circ }{\text{A}}$ each, the expected value of atomic radii of $K$ and $F$ should be:

1. $1.34\stackrel{\circ }{\text{A}}\text{and}1.34\stackrel{\circ }{\text{A}}$
2. $2.31\stackrel{\circ }{\text{A}}\text{and}0.64\stackrel{\circ }{\text{A}}$
3. $0.64\stackrel{\circ }{\text{A}}\text{and}2.31\stackrel{\circ }{\text{A}}$
4. $2.31\stackrel{\circ }{\text{A}}\text{and}1.34\stackrel{\circ }{\text{A}}$

Q.

What type of bond is B and H ?

Q. Which of the following hydrogen bonds is the strongest?

1. 
2. 
3. 
4. 

Q. Which of the following bonds will be most polar?

1. N - Cl
2. O - F
3. N - F
4. N - N

Q. Among $LiCl,BeC{l}_2,BC{l}_3$ and $CC{l}_4$ the covalent bond character follows the order

1. $LiCl>BeC{l}_2>CC{l}_4>BC{l}_3$
2. $BeC{l}_2>LiCl>BC{l}_3>CC{l}_4$
3. $LiCl<BeC{l}_2<BC{l}_3<CC{l}_4$
4. $LiCl>BeC{l}_2>BC{l}_3>CC{l}_4$

Q. Among the hydrides of Group-15 elements, which have the
(a) lowest boiling point?
(b) maximum basic character?
(c) highest bond angle?
(d) maximum reducing character?

Q. $\pi -$ bonding is not involved in :

1. ferrocene
2. dibenzene chromium
3. zeise's salt
4. grignard reagent

Q. In the atomic volume vs atomic weight of the elements graph, which of the following element occupies the peak position on the curve?

1. $K$
2. $Ca$
3. $Mn$
4. $Cl$

Q. In the atomic volume vs atomic weight of the elements graph, which of the following elements occupies a descending position on the curve?

1. $Na$
2. $Rb$
3. $Mg$
4. $Cl$

Q. Calculate the electronegativity of carbon from the following data:
Bond energy of H-H bond $E_{H-H}=104.2kcalmo{l}^{-1}$
Bond energy of C-C bond $E_{C-C}=83.1kcalmo{l}^{-1}$
Bond energy of C-H bond $E_{C-H}=98.8kcalmo{l}^{-l}$
Electronegativity of Hydrogen $X_H=\mathrm{2.1.}$

1. 3.75
2. -3.75
3. 2.59
4. -2.59

Q. which chalcogen element has least negative electron gain enthalpy? what does "LEAST NEGATIVE ELECTRON GAIN ENTHALPY" mean? does it mean more of metallic character or non metallic character?

Q. Which of the following element cannot form a $p\pi -d\pi$ bond?

1. N
2. P
3. As
4. All of the above

Q. Among the transition elements the element with lowest melting point belongs to:

1. Group $IIIB$
2. Group $IB$
3. Group $VIB$
4. Group $IIB$

Q. Which of the following bonds will be most polar?

1. O - F
2. N - F
3. N - N
4. N - Cl

Q. Which one among the following is the most acidic?

1. $A{s}_2{O}_3$
2. $S{b}_2{O}_3$
3. $N_2{O}_3$
4. $P_2{O}_3$

Q. Among the hydrides of Group-15 elements, which have the
(a) lowest boiling point?
(b) maximum basic character?
(c) highest bond angle?
(d) maximum reducing character?

Q. What are the trend for metallic and non - metallic characters?