Q9 of 17 Page 122

In the following table, the mass number and the atomic number of certain elements are given:


(a) Select a pair of isobars from the above table.


(b) What would be the valency of element ‘B’ listed in the above table?

a. Elements D and E are isobars as they have a same mass number but a different atomic number.

b. The atomic number of element B is 3. So its electronic configuration is 2, 1. Hence its valency is 1 as it has only 1 valence electron.


More from this chapter

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7

The number of electrons in the outermost shell of chlorine is 7. What is its valency and why?

 8

Write one pair of isobars. Why the chemical properties of isobars are not similar?

 10

(a) List any two postulates of Bohr’s model of an atom.

(b) Draw a sketch of Bohr’s model of an atom with four shells


(c) name the three sub-atomic particles.

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(a) What are the canal rays? State the nature of the constituents of canal rays.

(b) Who discovered canal rays?