which electrons in an atom make chemical bonds? why
The outer electrons, called valence electrons, are the ones that form chemical bonds because they are less strongly attached to the nucleus.
The electrons in the outermost energy level of an atom, called the valence electrons, are primarily responsible for making chemical bonds.
To understand why, we need to consider the electron configuration of an atom. Each shell or energy level of an atom can hold a certain number of electrons. The innermost shell is filled first, followed by the subsequent shells. The outermost shell, known as the valence shell, is the most important when it comes to forming chemical bonds.
Atoms tend to achieve a stable electron configuration by either gaining, losing, or sharing electrons. This stability is typically achieved by filling or emptying the valence shell, which follows the octet rule. According to the octet rule, atoms strive to have eight electrons in their valence shell, corresponding to the electron configuration of noble gases such as helium, neon, and argon.
When atoms interact chemically, they attempt to achieve this stable electron configuration by either sharing electrons with other atoms (covalent bond) or transferring electrons to or from other atoms (ionic bond). In both cases, it is the valence electrons that are involved in the bond formation.
For example, in covalent bonding, atoms share pairs of electrons in order to achieve a more stable configuration. Each atom contributes one or more valence electrons to the shared pair. By sharing these electrons, atoms can achieve a full valence shell and increase their stability.
In ionic bonding, one atom transfers one or more valence electrons to another atom, resulting in the formation of positively charged ions (cations) and negatively charged ions (anions). The attraction between these oppositely charged ions binds them together to form an ionic bond.
In summary, the valence electrons of an atom are involved in chemical bonding because they play a crucial role in achieving a stable electron configuration and increasing the stability of the atoms involved.