Available Answers

1. 1.

   Fill in the blanks with appropriate words:

   1. ___________ was the first scientist to use symbols for the atoms.
   2. Electrons were discovered by  ___________.
   3.  ___________ discovered protons.
   4. The electron is found to carry 1.602 x10^-19 coulombs of negative charge  ___________.
   5. Plum pudding model was given by  ___________.
2. 2.

   Complete the following table:

   Particle	Electron	Proton	Neutron
   1. Symbol	e-
   2. Nature		Positively charged
   3. Relative charge
   4. Absolute mass			1.67x10-24g

3. 3.

   Give two examples of elements that show:

   1. Positive electrovalency → ___________________ , ___________________
   2. Negative electrovalency → ___________________, ___________________
4. 4.

   With respect to Rutherford's scattering experiment, answer the following questions.

   1. What was the foil made-up of?
   2. Why did most of the alpha particles passed straight?
   3. "Very few alpha particles were deflected through some angles" What does this show?
   4. Which radiations were bombarded on gold foil?
   5. Which substance released the alpha particles?
5. 5.

   Fill in the blanks with suitable word:

   1. The bond formed by the transfer of an electron is called an ____________ bond.
   2. The bond formed by sharing of electron is known as ____________ bond.
   3. An atom loses an electron to form a positive ion known as ____________.
   4. An atom gains an electron to form a negative known as ____________.
6. 6.

   Complete the following table:

   Valence electronics	1	2	3	4	5	6	7	8
   Valency
   Metal / Non-metal