All important question from chapter structure of the atom class 9th
Answers
Answer:
Choose the correct option:
1. The nucleons are
(a) protons and electrons (b) neutrons and electrons
(c) protons and neutrons (d) none of these
2. The isotope deuterium of hydrogen has
(a) no neutrons and one proton (b) one neutron and two protons
(c) one electron and two neutron (d) one proton and one neutron
3. The electrons present in the outermost shell are called
(a) valency electrons (b) octate electrons
(c) duplet electrons (d) valence electron
4. An a-particle contains
(a) 4 positive charge and 2 mass unit
(b) 2 positive charge and 4 mass unit
(c) 2 positive charge and 2 mass unit
(d) 4 positive charge and 4 mass unit
5. The atomic number of sodium is 11 and its mass number is 23. It has
(a) 11 neutrons and 12 protons (b) 12 protons and 11 electrons
(c) 11 electrons and 12 neutrons (d) 12 electrons and 11 neutrons
6. The electronic configuration of chlorine is
(a) 2, 7 (b) 2, 8, 8, 7
(c) 2, 8, 7 (d) 2, 7, 8
7. The isotope used to remove the brain tumours and treatment of cancer is
(a) U-235 (b) Na-24
(c) Iodine (d) Co-60
8. The isobars definition.
9. The elements with same valence electrons and form same type of ions
10. In the α-scattering experiment, few α-particles rebounded because
(a) Most of the space in the atom is occupied.
(b) Positive charge of the atom occupies very little space.
(c) The mass of the atom is concentrated in the centre.
(d) all positive charge and mass of the atom is concentrated in small volume.
Answer: 1—(c), 2—(d), 3—(d), 4—(b), 5—(c), 6—(c), 7—(d),10—(d).