Question

a bond is when two atoms are to each other by their ?

Answer 1

There is Ionic and covalent bonds. Covalent is the sharing of electrons, Ionic is the losing of electrons (transferring to another atom). Look at the number of electrons in the outermost shell, they want to reach 8 electrons, the octate rule.

Answer 2

covalent bond is electron sharing between outer shell of two atoms to complete their octate. ionic bond is form between one atom losing the electron (cation) and another one is gain that electron(anion).