Chemistry homework
3. c) Why is magnesium a better electrical conductor than:
i) phosphorus?
ii) sodium?
Ans: Mg is a metal, and the atoms in molecule are bonded by metallic bonds. The atoms are arranged in
a giant lattice held together by a sea of delocalized electrons. So it is a good electrical conductor.
i) phosphorus has no free electrons that can move around and carry charge, hence it does not conduct
electricity.
ii) both Mg and Na are metals, and the atoms in molecules are bonded by metallic bonds. The atoms are
arranged in a giant lattice held together by a sea of delocalized electrons. Since Mg has 2 valence shell
electrons, and Na only 1, Mg can donate more electrons into the sea of delocalized electrons, hence the
electrical conductivity of Mg is better.
4. d) the outer most shell of As is 4p^3, so it has 3 unpaired electrons. The outer most subshell of Se is
4p^4, so it has 2 paired electrons in the first p orbital, and 2 unpaired electrons. Because of this pairing,
the electron-electron repulsion forces increases within the orbital, so it is easier to remove that paired
electron. Therefore, ionization energy of sulfur is lower than ionization energy of phosphorus.
762kJ/mol< Se<966kJ/mol