Transition metals have higher melting points and densities than group I metals because

  • A. their atoms are much larger
  • B. they contain no free electrons
  • C. both the d and s electrons take part in metallic bonding, giving a stronger and more compact lattice
  • D. they are non metallic in character

Explanation

A larger number of delocalised electrons per atom means stronger attraction between the cations and the electron sea, so more energy is needed to melt the metal and the atoms pack more closely, raising density. Group I metals contribute only one electron each and are correspondingly soft and low melting. This is why tungsten is used for lamp filaments and sodium can be cut with a knife.

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