III. EV
1. List out the two limitations of Dalton's atomic theory.
2. The charge of cathode rays is ------
3. Do the properties of anode rays depend upon the nature of the gas taken inside the
discharge tube?
4. Mass of proton (P) =
5. The valency of calcium in CaCl, is --------
6. Classify the following as monovalent, divalent and trivalent.
Ni 2+, Fe3+, Cu2+, Fe2+, Cr+, Li
7. The mass of neutron is equal to the mass of -------
8. Name the circular path in which the electrons are revolving around the nucleus?
9. What is the valency of Oxygen in the water molecule?
10. Who discovered the positively charged particles?
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Answers
Answer:
1)It does not account for subatomic particles: Dalton's atomic theory stated that atoms were indivisible. It does not account for isotopes: As per Dalton's atomic theory, all atoms of an element have identical masses and densities.
2) negatively charged
3)The nature of anode rays depends on the gas which is taken in the tubeas these rays are produced from thegases present in the tube. The different gases have different types of positive rays,that contain particles of different mass and charge. Therefore, the charge to mass ratio of anode depends on the gas.
4)15
5)2
6) sorry
7)0
8) electrons revolve around the nucleus in circular paths called orbits.
9)The valency of oxygen is 2, because it needs two atoms of hydrogen to form water.
10)Rutherford and other scientists decided that a positively charged particle must exist to center the electron to create equally neutral atoms. Thompson proposed the name 'positive rays'.