(a)(i) List the quantum number that are assigned to an electron in an atom. (ii) What is the maximum number of electrons that can occupy the 3d orbital?
(b) An element represented as P has the following electronic configuration: 1s\(^2\)2s\(^2\)2p\(^6\)2s\(^2\) (i) Write the electronic configuration of the ion of P. (ii) Without identifying P, write the likely formula of its chloride. (iii) State with reason, whether P will be a good oxidizing or reducing agent.
(c)(i) What is electron affinity? (ii) Explain briefly why ammonia can precipitate in dative bonding.
(d)(i) If an element in Group IV loses an alpha particle, to which group would the product belong? (ii) Two equally toxic substances X and Y which decay to non-toxic products, were absorbed through the skin. If their half-lives are 8 minutes and 2 months respectively, which of them constitutes the greater health hazard? Explain your answer
Explanation
(a)(i) Quantum numbers assigned to an electron in an atom are 9(i) n - (principal) quantum number (ii) L - (azimuthal) sub principal quantum number (iii) m - (magnetic quantum number) and (iv) s - (spin quantum number) (ii) The maximum number of electrons that can occupy the 3d orbital is 10.
(b) The element p represented by the electronic configuration 1s\(^2\)s\(^2\)2p\(^6\)3s\(^2\) (i) The electronic configuration of its ions is 1s\(^2\)2s\(^2\)2p\(^6\) Most likely formula of the chloride of P is PCl\(^2\) (iii) P is a good reducing agent. Reducing agents are electron donors OR P would readily lose 2(two) electrons to form noble gas structure.
(c)(i) Electron affinity is defined as the energy evolved or liberated when 1 mole of an element in form of gaseous atoms form negative ions OR The energy liberated or absorbed when one mole of electron is added to an element in form of gaseous atoms. (ii) Ammonia can participate in dative bonding because dative bonding involves the sharing of an electron pair donated by one atom. The nitrogen in ammonia has a lone pair of electrons which can be donated for sharing.
(d)(i) if an element in group IV loses an alpha particle, the product would belong to group II. (ii) Since both X and Y are equally toxic, Y constitutes a greater health hazard than X which has a shorter half life because half life is the time taken to decay to half the initial value remains for a longer period in the body and being toxic causes damage for a longer period.
