The number of electrons in the valence shell of elements A and B, are 6 and 7 respectively. What is the formula and type of bonding in a compound formed by these elements?

A.     \({{\text{A}}_{\text{2}}}{\text{B}}\), covalent

B.     \({\text{A}}{{\text{B}}_{\text{2}}}\), covalent

C.     \({{\text{A}}_{\text{2}}}{\text{B}}\), ionic

D.     \({\text{A}}{{\text{B}}_{\text{2}}}\), ionic

B