Q. No.1. Neutron
2. Alpha particle
3. Positron
4. Charge on the electrons
1. Pauli exclusion principle
2. Hund's rule
3. The wave properties of matter
4. Heisenberg uncertainty principle
When the atoms of gold sheet are bombarded with a beam of -particles, only a few alpha-particles get deflected where as most of them go straight undeflected. This is because:
| 1. | The force of attraction on the -particles by the oppositely charged electron is not sufficient. |
| 2. | The nucleus occupies much smaller volume as compared to the volume of atom. |
| 3. | The force of repulsion on fast moving -particles is very small. |
| 4. | The neutrons in the nucleus do not have any effect on -particles. |
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Which of the following statements about an electron is/are correct?
| (a) | It has a negative charge and is lighter than a proton. |
| (b) | It has a negative charge and is heavier than a proton. |
| (c) | Its position is less fixed than that of a proton. |
| (d) | Its position is more fixed than that of a proton. |
| 1. | (a) only | 2. | (a) and (c) |
| 3. | (b) and (d) | 4. | (c) only |
1. \({ }_{26}^{56} \mathrm{Fe}\text{ and }{ }_{28}^{58} \mathrm{Ni} \)
2. \({ }_{26}^{58} \mathrm{Fe}\text{ and }{ }_{26}^{56} \mathrm{Fe}^{2+} \)
3. \({ }_{27}^{57} \mathrm{Co}\text{ and }{ }_{28}^{57} \mathrm{Ni} \)
4. \({ }_{28}^{57} \mathrm{Ni}\text{ and }{ }_{28}^{58} \mathrm{Ni} \)
Identify the pairs which are not isotopes?
(a) \(_{6}^{12}X, \ _{6}^{13}Y\)
(b) \(_{17}^{35}X, \ _{17}^{37}Y\)
(c) \(_{6}^{14}X, \ _{7}^{14}Y\)
(d) \(_{4}^{8}X, \ _{5}^{8}Y\)
1. (a), (d)
2. (b), (c)
3. (c), (d)
4. (b), (d)
Which of the following statements about the electron is incorrect?
| 1. | It is a negatively charged particle. |
| 2. | The mass of electron is equal to the mass of neutron. |
| 3. | It is a basic constituent of all atoms. |
| 4. | It is a constituent of cathode rays. |
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Determine the identity of a species if it has 16 protons, 18 electrons, and 16 neutrons:
| 1. | \(S^{-}\) | 2. | \(Si^{2+}\) |
| 3. | \(P^{3-}\) | 4. | \(\mathrm{S}^{2-}\) |
1. 20.1
2. 20.2
3. 20.8
4. 21.2
In \(_{35}^{80}Br\), the number of protons, neutrons, and electrons are:
1. 25, 45, 45
2. 35, 45, 35
3. 45, 45, 35
4. 80, 35, 35
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