Electrons are negatively charged particles that can be either free or attached to the nuclei of atoms. While protons and neutrons are found inside the nucleus, electrons are located around the nucleus, in the electron cloud. These electrons fill the shells around the nucleus and the outermost shell is referred to as a valence shell. Electrons in the outer shell are called valence electrons, respectively. If you are not aware of what the purpose of these electrones is, we’ve got you covered. Here are ten reasons why valence electrons are so important:
#1. Valence electrons affect an atom’s electronegativity
Electronegativity is a chemical property that measures the tendency or power of an atom to attract electron density (or electrons) from another atom to itself. As you may already know, periodic trends also apply to electronegativity. When moving across a row (period) from left to right, the electronegativity of elements increases. This is because the nuclear charge of elements increases and the atomic size decreases. The increase in the electronegativity from left to right across a period can be explained by the fact that the elements with more valence electrons need only a few electrons to complete their valence shells, and therefore, are the most electronegative.
#2. Valence electrons govern an atom’s electron affinity
Oftentimes, people confuse an atom’s electronegativity with its electron affinity. The truth is that these two terms describe different quantities of atoms. Electron affinity refers to the energy (in kJ/mol) released or absorbed when a neutral gas-phase atom receives an electron. It can also be defined as the neutral atom’s tendency to gain an electron and form a negative ion. Atoms with more valence electrons acquire electrons more easily and have a higher electron affinity. Since nonmetals have more valence electrons than metals, nonmetals are characterized by a higher electron affinity when compared to metals.
#3. Valence electrons influence an atom’s ionization energy
Ionization energy is the amount of energy required to remove the most loosely bound electron from a neutral gas-phase atom. Since valence electrons are the farthest from the atom’s nucleus, they are the least tightly bound electrons. Therefore, removing valence electrons is easier. Besides, a larger atomic radius or more valence shell electrons correspond to lower ionization energy. This explains the fact that ionization energy decreases as you go down a column (group) in the periodic table.
#4. Valence electrons determine an atom’s stability
Valence electrons are also responsible for a given atom’s stability. According to the Octet Rule, atoms tend to gain or lose electrons to achieve the octet state, or have eight electrons in their valence shell. At this point, they become stable. Examples of stable elements are inert gases, which feature eight electrons in the valence shell.
#5. Valence electrons alter an atom’s reactivity
An atom’s stability also influences its reactivity. When atoms have eight electrons in their valence shells, they are considered less reactive since they are already stable and no longer need to lose or gain electrons to satisfy the octet rule. Contrarily, atoms with less than eight valence electrons in the outermost shell react with other atoms to become stable. Evidently, the number of valence electrons determines the tendency of an atom to be either reactive or inert.
#6. Valence electrons determine how atoms interact with other atoms or molecules
As mentioned above, valence electrons govern an atom’s stability and reactivity. Besides, the number of valence electrons helps us predict how a given atom will interact with other atoms or molecules. For instance, atoms might share electrons with each other or one atom might transfer its valence electrons to another. While electron transfer occurs when the atoms have different electronegativities, electrons are shared between the species when the difference between the electronegativity values is too small.
#7. Valence electrons are responsible for chemical bond formation
When electrons are transferred from one species to another or electrons are shared between them, a chemical bond is formed. Therefore, the bond formation process also involves valence electrons. When valence electrons are transferred from one atom to another, an ionic bond is formed. If valence shell electrons are shared between two or more atoms, a covalent bond is formed. Metallic bonding is a special case in which free electrons are shared within the lattice of positively charged ions (cations) and exist as a cloud of electrons around the ion centers.
#8. Valence electrons play a crucial role in chemical reactions
When reactants are converted into products, chemical bonds are broken down and formed. Hence, chemical reactions heavily depend on valence electrons. Without transferring or sharing electrons from the outermost shells, atoms would not be able to react with each other and form new compounds.
#9. Without valence electrons, there would not be any compound on earth
As mentioned earlier, valence shell electrons are responsible for chemical bond formation, which is the basis for various chemical reactions. Without valence electrons, there would not have been any chemical reactions occurring on earth, meaning that there would not have been any compounds whatsoever. With no valence electrons, our planet would not have existed at all.
#10. Without valence electrons, we would not even exist
Without chemical reactions and bonds, there would not have been any compounds, even those essential for life. No foods, no drinks, no medicine, no detergents, no nothing. Without these essential products, humans would not have existed. Clearly, valence electrons are of fundamental importance to humankind.
