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Answer is valance electrons
➡️A chemical bond is defined as an attractive force that holds the constituents (atoms, ions etc.) together in a chemical species.✔️
➡️Various theories have been suggested for the formation of chemical bonds such as the electronic theory, valence shell electron pair repulsion theory, valence bond theory, and molecular orbital theory.✔️
➡️A chemical bond formation is attributed to the tendency of a system to attain stability. ✔️
➡️It was observed that the inertness of noble gases was because of their fully filled outermost orbitals.✔️
➡️Hence, it was postulated that the elements having incomplete outermost shells are unstable (reactive). ✔️
➡️Atoms, therefore, combine with each other and complete their respective octets or duplets to attain the stable configuration of the nearest noble gases. ✔️
➡️This combination can occur either by sharing of electrons or by transferring one or more electrons from one atom to another.✔️
➡️The chemical bond formed as a result of sharing of electrons between atoms is called a covalent bond. ✔️
➡️An ionic bond is formed as a result of the transference of electrons from one atom to another.✔️
