Periodic table Quiz-06

Periodic table Quiz-06

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Q1.   The electrons used in bonding atoms:

•  Belong to outermost shell
•  Belong to penultimate shell
•  Belong to outermost shell and sometimes penultimate shell
•  Belong to penultimate shell and sometimes to outermost shell

Solution
(c) In transition elements, penultimate shell electrons also participate in bonding.

Q2.   Which property is commonly exhibited by a covalent compound?

•  High solubility in water
•  Low m.p.
•  High electrical conductivity
•  High b.p.

Solution
(b) Covalent compounds have lower m.p. and b.p. than ionic one.

Q3.   Which of the following are not correct?

•  Lone pair of electrons present on central atom can give rise to dipole moment
•  Dipole moment is vector quantity
•  CO_2 molecule has dipole moment
•  Difference in electronegativities of combining atoms can lead to dipole moment

Solution
(c) CO_2 is linear molecule.

Q4.   The electronegativity difference between N and F is greater than that between N and H yet the dipole moment of NH_3 (1.5 D) is larger than that of NF_3 (0.2 D). this is because:

•  In NH_3 as well as NF_3 the atomic dipole and bond dipole are in opposite directions.
•  In NH_3 the atomic dipole and bond dipole are in the opposite directions whereas in NF_3 these are in the same direction.
•  In NH_3 as well as in NF_3 the atomic dipole and bond dipole are in the same direction.
•  In NH_3 the atomic dipole and bond dipole are in the same direction whereas in NF_3 these are in opposite directions.

Solution
(d)        

Q5.   Correct increasing order of first ionisation potential is

•  NaAl
•  Na
•  Na>Mg>Al>Si
•  NaSi

Solution
(a) The ionisation energy increases when we move from left to right in a period. But this increase is not regular. The members of second group have greater ionisation potential as compared to third group due to stable configuration. Ionisation potential has following order NaAl

Q6.   Which element has the lowest electronegativity?

•  Li
•  F
•  Cl
•  Fe

Solution
(a) _3 Li-1s^2 2s^1 donates one electron easily

Q7.   Compound formed by sp^3 d-hybridization will have structure:

•  Trigonal bipyramidal
•  T-shaped
•  Linear
•  Either of these depending on number of lone pair of electrons of central atom

Solution
(d) sp^3 d-hybridisation leads to trigonal bipyramidal geometry if no lone pair is present, e.g.,PCl_5; in ClF_3 geometry is T shaped due to the presence of two lone pair of electron. In XeF_2, geometry is linear due to the presence of three lone pair of electrons.

Q8.   Which of the following two are isostructural?

•  XeF_2,IF_2^-
•  NH_3,BF_3
•  CO_3^(2-),SO_3^(2-)
•  PCl_5,ICl_5

Solution
(a) Both are linear.

Q9.   Which of the following has highest bond angle?

•  H_2 O
•  H_2 S
•  NH_3
•  PH_3

Solution
(c) Bond angles decrease down the group.

Q10.   The incorrect statements regarding bonding molecular orbitals because:

•  Bonding molecular orbital possess less energy than combining atomic orbitals
•  Bonding molecular orbitals have low electron density between the two nuclei.
•  Every electron in bonding molecular orbitals contributes to attraction between atoms.
•  They are formed when the lobes of the combining atomic orbitals have same sign.

Solution
(b) They have high electron density.