Question

why don't NaCl form covalent bond? why don't CH4 form ionic bond?

Answer 1

because in NaCl the valence shell in sodium is 1 and to form covalent bond it needed more than two or three electron in the valence shell and ch4 have to a two and more electrons in the valence shell that's why it forms covalent bond whereas NaCl form ionic bond

Answer 2

i think na loses electron and cloride gains electron to complete their octet

sodium                                                            cloride    

2,8,1 its imposible to gain 7e                         as cloride needs 1 electron to complete

so it loses its electron                                               their octet and its easy to gain it

Na+                       and                                                                     Cl-

as Ionic bonding is the complete transfer of valence electron(s) between atoms

ch4 ;methane;

carbon atom

2,4 it needs 4 electrons to complete their octet

there is no chance of lossing electrons becoz the force needs to hold 4 electros in their shells ,if 1 electron is lossed then the same force act on 3 electrons then we have need to give lot of energy to get another electron

so its better for  carbon aton to share electron with another atoms

therefore it forms covelent bond

thanks---