How Lewis dot structure helps in understanding bond formation between atoms?

i) The valence electrons with the atom of an element is depicted in a short form by Lewis symbol is electron dot structure.
ii) We represent the nucleus and inner shell electrons of the atom by the symbol of the element and electrons in the outer shell by dots or cross mark.
iii) Basing on the Lewis dot structure we can understand the valence of an element. Basing on the valence we can predict that it may form ionic bond or covalent bond.