Question

What are the major differences between metals and non-metals?

The increasing order of reactivity among group 1 elements is Li < Na < K < Rb <Cs whereas that among group 17 elements is F > CI > Br > I. Explain.

The first (∆iH1) and the second (∆iH2) ionization enthalpies (in kJ mol–1) and the (∆egH) electron gain enthalpy (in kJ mol–1) of a few elements are given below: | Elements | ∆H1 | ∆H2 | ∆egH | |----------|------|------|-------| | I | 520 | 7300 | –60 | | II | 419 | 3051 | –48 | | III | 1681 | 3374 | –328 | | IV | 1008 | 1846 | –295 | | V | 2372 | 5251 | +48 | | VI | 738 | 1451 | –40 | Which of the above elements is likely to be :

Considering the elements B, Al, Mg, and K, the correct order of their metallic character is :