Enlist the conclusions drawn by Rutherford from his α-ray scattering experiment.
Answer: Rutherford’s conducted an experiment by bombarding a thin sheet of gold with α-particles and then studied the trajectory of... View Article
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The ratio of the radii of hydrogen atom and its nucleus is ~ 105. Assuming the atom and the nucleus to be spherical, (i) What will be the ratio of their sizes? (ii) If atom is represented by planet earth ‘Re ’ = 6.4 ×106 m, estimate the size of the nucleus.
Answer: Assuming the atom and the nucleus to be spherical. (i) What will be the ratio of their sizes? Atomic... View Article
Why do Helium, Neon and Argon have a zero valency?
Answer: Valency is a combining capacity of an element. As there are no free electrons in the valence shell and... View Article
An element X has a mass number 4 and atomic number 2. Write the valency of this element?
Answer: Mass number = 4 Atomic number = 2 X is Helium. It has 0 valency and it will not... View Article
The electronic configuration of silicon is ______and that of sulphur is ______
Answer: The electronic configuration of silicon is 2.8.4 and that of sulphur is 2.8.6. Electronic configuration of silicon In the... View Article
Neon and chlorine have atomic numbers 10 and 17 respectively. Their valencies will be______and______respectively.
Answer: Neon and chlorine have atomic numbers 10 and 17 respectively. Their valencies will be 0 and 1 respectively. Valency... View Article
Isotopes have same ______but different______.
Answer: Isotopes have the same atomic number but a different mass number. Isotopes An isotope is any form of a... View Article
Rutherford’s α-particle scattering experiment led to the discovery of the ______
Answer: Rutherford’s α-particle scattering experiment led to the discovery of the atomic nucleus. Rutherford atomic model According to the Rutherford... View Article
Helium atom has 2 electrons in its valence shell but its valency is not 2, Explain
Answer: He(z = 2) = 1s2 The electronic configuration of a helium atom 1s2 and which is a noble gas... View Article
Complete Table 4.1 on the basis of information available in the symbols given below (a) 35 17 Cl (b) 12 6 C (c) 81 35 Br
(a) 3517 Cl (b) 126C (c) 8135 Br Element np nn ... View Article
The atomic number of calcium and argon are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements?
Answer: The total number of protons in the nucleus of an atom gives us the atomic number of that atom.... View Article
Match the names of the Scientists given in column A with their contributions towards the understanding of the atomic structure as given in column B (A) – (B) (a) Ernest Rutherford – (i) Indivisibility of atoms (b) J.J.Thomson – (ii) Stationary orbits (c) Dalton – (iii) Concept of the nucleus (d) Neils Bohr – (iv) Discovery of electrons (e) James Chadwick -(v) Atomic number (f) E. Goldstein – (vi) Neutron (g) Mosley – (vii) Canal rays
Answer: A B (a) Ernest Rutherford (iii) Concept of the nucleus (b) J.J.Thomson (iv) Discovery of electrons (c) Dalton (i)... View Article
Calculate the number of neutrons present in the nucleus of an element3115X which is represented as
Answer: The total number of protons in the nucleus of an atom gives us the atomic number of that atom.... View Article
In response to a question, a student stated that in an atom, the number of protons is greater than the number of neutrons, which in turn is greater than the number of electrons. Do you agree with the statement? Justify your answer.
Answer: The statement is wrong because the number of protons can never be greater than the number of neutrons. The... View Article
What information do you get from the Fig. about the atomic number, mass number and valency of atoms X, Y and Z? Give your answer in a tabular form.
Answer: The total number of protons in the nucleus of an atom gives us the atomic number of that atom.... View Article
In the atom of an element X, 6 electrons are present in the outermost shell. If it acquires noble gas configuration by accepting requisite number of electrons, then what would be the charge on the ion so formed?
Answer: The noble gas’s electronic configuration is 2,8. In its outermost orbitals, it has 8 electrons. The outermost shell of... View Article
Write down the electron distribution of chlorine atom. How many electrons are there in the L shell? (Atomic number of chlorine is 17).
Answer: The atomic number of chlorine is 17. Hence it has 2 electrons in its innermost shell, 8 electrons in... View Article
One electron is present in the outer most shell of the atom of an element X. What would be the nature and value of charge on the ion formed if this electron is removed from the outer most shell?
Answer: If an electron is removed from the outermost shell a cation will be formed and the charge of the... View Article
Find out the valency of the atoms represented by the Fig. (a) and (b).
Answer: Atom (a) has zero valencies as it has 8 electrons in its valence shell making the configuration stable. Atom... View Article
Why did Rutherford select a gold foil in his α–ray scattering experiment?
Answer: Rutherford intended a metal sheet that could be as thin as appropriate for the scattering experiment. The most malleable... View Article
