(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
(a)(i) Quantum numbers assigned to an electron in an atom are:
- Principal quantum number, n
- Azimuthal (angular momentum) quantum number, l
- Magnetic quantum number, ml
- Spin quantum number, ms
(ii) The maximum number of electrons that can occupy the 3d subshell is 10.
(b) The configuration is taken as \(1s^2\,2s^2\,2p^6\,3s^2\).
(i) P loses two electrons to form P2+. Its electronic configuration is:
\(1s^2\,2s^2\,2p^6\)
(ii) The likely formula of the chloride of P is PCl2.
(iii) P is a good reducing agent because it readily loses two outer electrons to attain a stable noble-gas configuration. Thus, it donates electrons to other substances.
(c)(i) Electron affinity is the energy evolved or absorbed when one mole of electrons is added to one mole of gaseous atoms to form one mole of gaseous negative ions.
(ii) Ammonia can participate in dative bonding because the nitrogen atom has a lone pair of electrons which it can donate to an electron-deficient atom or ion for sharing.
(d)(i) On losing an alpha particle, the atomic number decreases by 2. Therefore, an element in Group IV will give a product in Group II.
(ii) X, with a half-life of 8 minutes, constitutes the greater health hazard. Its shorter half-life means that it decays more rapidly and releases radiation at a higher rate than Y within a given period.
(a)(i) Quantum numbers assigned to an electron in an atom are:
- Principal quantum number, n
- Azimuthal (angular momentum) quantum number, l
- Magnetic quantum number, ml
- Spin quantum number, ms
(ii) The maximum number of electrons that can occupy the 3d subshell is 10.
(b) The configuration is taken as \(1s^2\,2s^2\,2p^6\,3s^2\).
(i) P loses two electrons to form P2+. Its electronic configuration is:
\(1s^2\,2s^2\,2p^6\)
(ii) The likely formula of the chloride of P is PCl2.
(iii) P is a good reducing agent because it readily loses two outer electrons to attain a stable noble-gas configuration. Thus, it donates electrons to other substances.
(c)(i) Electron affinity is the energy evolved or absorbed when one mole of electrons is added to one mole of gaseous atoms to form one mole of gaseous negative ions.
(ii) Ammonia can participate in dative bonding because the nitrogen atom has a lone pair of electrons which it can donate to an electron-deficient atom or ion for sharing.
(d)(i) On losing an alpha particle, the atomic number decreases by 2. Therefore, an element in Group IV will give a product in Group II.
(ii) X, with a half-life of 8 minutes, constitutes the greater health hazard. Its shorter half-life means that it decays more rapidly and releases radiation at a higher rate than Y within a given period.
