化学方面的问题。

show how covalent bonding occurs in each of the following pairs of atoms.atoms may share one,two or three pairs of electrons.

1.H+H(H2)

2.F+F(FS)

3.O+O(O2)

4.N+N(N2)

5.C+O(CO2)

6.H+O(H2O)

我觉得是3氧气。