9701 MCQ Solution 44

Question 44: [Physical > Atomic Structure]

Reference: Past Exam Paper -June 2003 Paper 1 Q4

Solution 44:

Answer: C

Ionisation energy is the energy required to remove an electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous ions. We can see a general increase in ionisation energies of element X because as each electron is removed from the outer shell the shielding effect decreases and the distance between the nucleus and electron decrease because as electrons are removed the protons become more in number than electrons therefore the nuclear charge increase and the protons force of attraction of electrons increase therefore resulting in an even smaller atom than the usual atom . therefore the ion now is more stable than the usual atom. its easy to identify the element by looking at the sharp increase , sharp increase in ionisation energies indicate that all electrons that were in the outermost shell were removed , number of shells now decreased therefore resulting in even more than a smaller atom , therefore a huge amount of energy is now required to remove the next electron that is close to the nucleus. if we look at the question the sharp increase is after the 6th ionisation energy this indicates that the 7th electron is in a shell closer to the nucleus and that there is 6 electrons in the outermost shell. number of electrons in the outer shell indicates the group number of the element, Te is the only element from group 6 in the options given therefore the answer is C.