Structure of Atom

The percentage of copper and oxygen in samples of “CuO” obtained by different methods were found to be the same. This illustrates the law of:

• Constant proportions

• Conservation of mass

• Multiple proportions

• Reciprocal proportions

• Law of conservation of mass

• Law of definite proportions

• Law of multiple proportions

• Law of reciprocal proportions

In a chemical reaction 150 g Baking soda mixture containing sodium bicarbonate and vinegar on heating gives 87 g of carbon dioxide gas. What mass of solid residue will be left in food?

• 53 g

• 63 g

• 73 g

• 237 g

The postulates of Dalton's Atomic Theory did not satisfy

• Isotopes

• Isobars

• the fact that atom is divisible

• All of these

Select the incorrect statement about Cathode rays

• The charge to mass ratio of cathode rays does not depend on the nature of gas

• Cathode rays travel in straight lines in absence of electric and magnetic field

• Cathode rays move towards the anode

• Cathode rays consist of positively charged gaseous ions

The number of neutrons in ₁₈Ar⁴⁰ is

• 18

• 40

• 22

• 20

Select the incorrect statement about anode rays

• Anode rays are positively charged gaseous ions.

• The charge to mass ratio of anode rays does not depend on the nature of gas

• Anode rays travel towards cathode

• Anode rays travel in straight lines in the absence of electric and magnetic field.

The image shown here best describes the

• Thomson's Plum Pudding Model

• Rutherford's Nuclear Model

• Bohr's Atomic Model

• Quantum Mechanical Atomic Model

In the image shown, most of the alpha particles passed through the thin gold foil undeflected. This shows that

• Electrostatic force is a short range force

• Most of the space inside an atom is empty

• Protons are uniformly distributed and their mass is negligible in comparison to alpha particles

• Neutrons are neutral in charge

The charge on an electron is

• 1.602 x 10^-19 C

• - 1.602 x 10^-19 C

• 1.602 x 10¹⁹ C

• -1.602 x 10¹⁹ C