Coulomb’s Law and intermolecular forces have a very strong relationship One cannot be relevant without the other They work hand and hand to give us an outcome to an equation Charles Augustin de Coulomb was a physicist and military engineer from France Once he graduated college in the 1700s he joined the military at the lieutenant position After twenty five plus years he returned to France and was employed at a western city called La Rochelle As he was working here He discovered a inverse relationship of the force between electric charges and the square of its distance then the same relationship between magnetic poles These two relationships were later named after him Coulomb's Law describes the relationship between electrically charged objects The formula helps you define the relationship between the two objects where F is the electrostatic force k represents a constant value sometimes called Coulomb's constant q1 represents the charge of the first object q2 represents the charge of the second object and r represents the distance between the two charges The unit used to measure charges in this equation is coulomb Ionization energy is as the name would imply the energy needed to make an atom into an ion by removing an electron Coulomb s Law shows why ionization energy decreases as you go down a group As you go down a group valence electrons are higher in energy level which are farther from the nucleus so force of attraction is less therefore less energy is needed to remove electrons
This law also tells us why ionization energy increases as you go across a period As you go across a period the nuclear charge increases so the force of attraction increases therefore more energy is needed to break the force The Law also tells us about the atom s structure The electrons are held together by the protons located in the nucleus as Coulomb's Law predicts Intermolecular forces are the forces which moderate interaction between molecules including forces of attraction or repulsion which act between molecules and other particles Johannes Diderik van der Waals came up with the ideas of intermolecular forces The three types of major molecular forces are London dispersion force dipole dipole interaction and ion dipole interaction a dipole refers to the separation of charges within a molecule between two covalently bonded atoms The london dispersion force is the weakest dispersion force It is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles Dipole Dipole interactions result when two dipolar molecules interact with each other through space An ion dipole interaction is the result of an electrostatic interaction between a charged ion and a molecule that has a dipole To determine intermolecular forces the bottom line is that the intermolecular forces increase with increasing polarization of bonds Also the boiling increases with the molecular weight and with the surface area
The strength of the forces also affect the strength of the intermolecular bonds There are a few intermolecular force present in covalent bonds Hydrogen bonds are located in covalent bonds The hydrogen bond is often described as a strong electrostatic dipole dipole interaction Intermolecular hydrogen bonding is the reason for the high boiling point of water which is one hundred degrees celsius The dipole dipole attraction only happens between partially oppositely charged ions The dipole dipole attraction is also the strongest bond Hydrogen bonds only occur w certain atoms It is at the same level of strength as the dipole dipole attraction The london dispersion attraction only happens between temporary and induced dipoles It is the weakest of the intermolecular bonds Without the creation of intermolecular forces solids and liquids would not exist in this world With the background of Coulomb's Law this helps you determine the strongest intermolecular forces Just like bonding the intermolecular forces are based on the Coulomb Law The electrical force between charged particles is one of the four kinds of forces in the universe We call this the electrostatic force We describe these forces using Coulomb's law The Coulomb force is the strongest of the intermolecular forces it used for the ionic bonding of salts such as nitrogen chloride We need a way to measure the relative strengths of dipoles because a dipole can exert a force on another atom or molecule and the amount of force exerted will depend on the strength of the dipole The strength of a dipole depends on how much charge difference exists between one end of a molecule and another and the separation of those ends We call the measure of dipole strength the dipole moment A moment is a measure of shape
The dispersion force is a purely quantum mechanical force and can only be truly understood by applying the law of quantum mechanics to the outer electrons of atoms From time to time in an atom the electron density is momentarily unbalanced momentarily spoiling the spherical symmetry and forming a small dipole This moment can induce a similar fluctuation in the other atom and so on Such fluctuations can become correlated producing an overall attraction between atoms that we might otherwise think would be no mechanism of attraction That s roughly what the dispersion force is We have seen that charges and regions of relative charge difference can interact to attract and repel each other How does a non charged and nonpolar atom molecule interact with a dipole It turns out that a dipole can cause a dipole moment in say an atom The force between charged particles is directly related to the amount of charge carried by each particle Other than electrons and protons most charged particles carry a amount of charge
