Advertisements
Advertisements
प्रश्न
What do you mean by polar molecules and non-polar molecules? Give ‘one’ example each.
Advertisements
उत्तर
Polar molecules: The molecules in which “centre of gravity” of positive nuclei and revolving electrons do not coincide are known as polar molecules.
Example: HCl, H2O, N2O etc.
Polar substances behave as a tiny electric dipole because polar molecules have a permanent electric dipole moment.
Non-polar molecules: The molecules in which “centre of gravity” of positive nuclei and revolving electrons coincide are known as non-polar molecules.
Example: O2, H2, CO2, polyethelene, polystyrene etc.
Non-polar molecules do not have permanent electric dipole moment because of their
symmetry.
APPEARS IN
संबंधित प्रश्न
In the study of Geiger-Marsdon experiment on scattering of α particles by a thin foil of gold, draw the trajectory of α-particles in the coulomb field of target nucleus. Explain briefly how one gets the information on the size of the nucleus from this study.
From the relation R = R0 A1/3, where R0 is constant and A is the mass number of the nucleus, show that nuclear matter density is independent of A
Two stable isotopes of lithium `""_3^6"Li"` and `""_3^7"Li"` have respective abundances of 7.5% and 92.5%. These isotopes have masses 6.01512 u and 7.01600 u, respectively. Find the atomic mass of lithium.
The three stable isotopes of neon: `""_10^20"Ne"`, `""_10^21"Ne"` and `""_10^22"Ne"` have respective abundances of 90.51%, 0.27% and 9.22%. The atomic masses of the three isotopes are 19.99 u, 20.99 u and 21.99 u, respectively. Obtain the average atomic mass of neon.
Obtain approximately the ratio of the nuclear radii of the gold isotope `""_97^197 "Au"` and the silver isotope `""_47^197"Ag"`.
Find the Q-value and the kinetic energy of the emitted α-particle in the α-decay of `""_88^226 "Ra"`.
Given `"m"(""_88^226"Ra")` = 226.02540 u, `"m"(""_86^222 "Rn")` = 222.01750 u,
`"m"(""_86^220 "Rn")`= 220.01137 u, `"m"(""_84^216 "Po")`= 216.00189 u.
Name a material which is used in making control rods in a nuclear reactor.
With the help of a suitable example and an equation, explain the term pair production.
Potassium-40 can decay in three modes. It can decay by β−-emission, B*-emission of electron capture. (a) Write the equations showing the end products. (b) Find the Q-values in each of the three cases. Atomic masses of `""_18^40Ar` , `""_19^40K` and `""_20^40Ca` are 39.9624 u, 39.9640 u and 39.9626 u respectively.
(Use Mass of proton mp = 1.007276 u, Mass of `""_1^1"H"` atom = 1.007825 u, Mass of neutron mn = 1.008665 u, Mass of electron = 0.0005486 u ≈ 511 keV/c2,1 u = 931 MeV/c2.)
What is a neutrino?
Nuclear species or nuclides are shown by the notation ________ where X is the chemical symbol of the species.
Nuclides with same neutron number N but different atomic number Z are called ______.
A vessel contains oil (density 0.8 g/cm3) over mercury (density 13.6 g/cm3). A sphere of homogeneous composition floats with half its volume immersed in mercury and the other half in oil. The density of the material of the sphere in g/cm3 is ______.
Before the neutrino hypothesis, the beta decay process was throught to be the transition, `n -> p + vece`. If this was true, show that if the neutron was at rest, the proton and electron would emerge with fixed energies and calculate them. Experimentally, the electron energy was found to have a large range.
Two nuclei may have the same radius, even though they contain different numbers of protons and neutrons. Explain.
What conclusion is drawn from Rutherford’s scattering experiment of α-particles?
What is ‘Pair production’?
A nucleus with mass number 240 breaks into two fragments each of mass number 120, the binding energy per nucleon of unfragmented nuclei is 7.6 MeV while that of fragments is 8.5 MeV. The total gain in the binding energy in the process is:
The volume occupied by an atom is greater than the volume of the nucleus by a factor of about:
Energy equivalent of 1 amu is:
In his experiment verifying neutral matter inside the nucleus, James Chadwick observed neutral radiation when beryllium nuclei were bombarded with:
The value of one atomic mass unit (1 u) is:
The nucleus of the lightest atom of hydrogen is called the:
All nuclides with the same mass number are called:
The mass of a neutron in atomic mass units is:
The number of protons in the nucleus is equal to:
Isotopes have identical chemical behaviour because:
