Atomic Structure (Combined Science) - Sample Questions

Analysis of the May/June Session 2000 Paper II - 5070/3


Sol to A4 Helium-6 & Helium-7 are isotopes. The nucleon mass number of Helium-6 is 6
and of helium-7 is 7. Compare the number of electrons, neutrons, and protons in one-atom of helium-6 and one-atom of helium-7.
c. Explain why helium does not react with other elements to form compounds
Isotopes have same no. of protons (same element) with differing nos. of neutrons(proton number/atomic number/nucleon numbers/mass number)
bi. Electrons 2 (same) ii. Protons 2(same) iii. Neutron 4 and 5 (one more)
c. Helium has a full outer shell or stable configuration , neither gains or loses electrons



Which electron arrangements is that of a Halogen?
A.electron arrangement Y
Belectron arrangement Z
C.electron arrangement X
D.electron arrangement W
Which electron arrangements correspond to two elements on the same period of the Periodic Table?
A.electron arrangement W and Z
B.electron arrangement Y and Z
C.electron arrangement X and Z
D. electron arrangement W and X

Sol A.The reactive non-metallic Halogens are Group 7, with 7 outer electrons, its the top element in the group, next to the last on Period 2 (2 shells used)
Sol A. both in the same period, period 2, 2 shells used