Give the mass and charge of an electron

2

(a)

Comment on the statement: "Electron are constituent of all matter".

2

(a)

State three characteristics of Canal rays.

2

(a)

What are cathode rays and positive rays?

2

(a)

What was the basis on which Rutherford rejected the model of atom as proposed by J.J Thomson?

2

(a)

What do you think would be the observation if the \(\alpha\)-particle scattering experiment is carried out using a foil of a metal other than gold?

2

(a)

(a) Write its electronic configuration.
(b) What is its valency and why?

2

(a)

Define the terms
(i) atomic number
(ii) mass number, of an atom in an element.

2

(a)

Define the term isotope with a suitable example.

2

(a)

Calculate the average atomic mass of Chlorine of it exists commonly in two isotopes \(_{17}^{32}Cl\) (75%) and \(_{17}^{37}Cl\)(25%). 

2

(a)

The number of protons, neutrons and electrons in species from A to E are given in the following table:

Species	Protons	Neutrons	electrons
A	6	6	4
B	18	22	18
C	17	20	17
D	9	10	11
E	17	18	17

Indicate from the above table the species that represent:
(i) A cation
(ii) An anion
(iii) An atom of inert gas
(iv) A pair of isotopes.

2

(a)

The average atomic of a sample of an element Y is 35.5u.What are the percentages of isotopes \(_{17}^{37}Y\) and \(_{17}^{35}Y\) in the sample.

2

(a)

For the symbol H, D and T tabulate three sub-atomic particles found in each of them.

2

(a)

Write the electronic configuration of any one pair of isotopes and isobars.

2

(a)

The distribution of electrons into different orbits of atoms was suggested by Bohr and Bury. The maximum number of electrons in a shell is given by 2n² where n is the orbit number or energy level. i.e., K, L, M, N.Further shells are filled in a stepwise manner, and that the outermost shell cannot accommodate more than 8 electrons. Shyam was given to give the distribution of 20 electrons contained in an atom. he suggested the distribution as 2, 8, 10 as per formulation (2n²)
(a) What should be the correct distribution? Which shells are completely filled?
(b) What were the moral values given by the teacher to Shyam?

2

(a)