Structure of the atom Worksheet-8

Structure of the atom Worksheet-8


  1. Out of proton and neutron, which is heavier?


  1. Were neutrons known at the time Rutherford performed the scattering experiment?


  1. Why is proton so named?


  1. The cation is represented as M3+ What is the difference between the number of protons and electrons present?


  1. What is the name of element whose atom has K and L shell completely filled ? To which group it belongs?


  1. Do isobars have also identical chemical characteristics like isotopes ?


  1. The electronic configuration of an element is : 2(K), 8(L), 5(M). Predict its valency.


  1. What is the basic difference between the isotopes of an element?


  1. The element aluminium is written by the symbol 13AI27. Write the number of protons, electrons and neutrons present in it.


  1. What is the number of electrons in the valence shell of chlorine (Z = 17)?



  1. Neutron is slightly heavier (1.675 × 10–27 kg) than proton (1.67 × 10–27 kg).


  1. No, neutrons were discovered later on by Chadwick in 1931 whereas scattering experiment was performed by Rutherford in 1911.


  1. Proton (H+) is formed when hydrogen atom

also called protium, loses an electron.


  1. In cation M3+, there are three protons more as compared to electrons. M3+ is formed when an atom of M loses 3 electrons.

M ® M3+ + 3e


  1. The element is neon (Ne) Atomic number -10 electronic distribution: K(2), L(8)

It belongs to zero groups.


  1. Isotopes have same atomic number hence similar electronic configurations. Whereas Isobars have different atomic numbers. Their electronic configurations also differ. Hence they have different chemical properties.


  1. The valency of the element is 3. It is calculated as: 8 - 5 = 3. The element belongs to group 5.


  1. Isotopes of an element differ in the number of neutrons leading to different mass numbers.


  1. No. of protons = 13

No. of electrons = 13

No. of neutrons = 27 – 13 = 14.


  1. The electronic distribution of Cl is 2,8,7 Valence shell of chlorine has 7 electrons.