Organic Chemistry Questions and Short Answers

Several characteristic properties of the metals are due to the nature of the metallic bond. Some unique properties include- 

1. High Melting and Boiling points: 

London dispersion forces are the weak intermolecular forces that occur when the molecules are in close proximity to each other. The strength of these forces is determined by the atomic size of the element.

In smaller atoms, the atomic radius is smaller, which means that the positively charged nucleus holds the outermost valence electrons more firmly, leaving less room for their dispersion or polarization.

The strength of polar-nonpolar interactions is affected by the atomic size of the nonpolar atom (or molecule) and the electronegativity of the polar molecule. 

Debye intermolecular forces of attraction occur between polar and nonpolar atoms or molecules. When closely placed with a polar molecule (electronegativity difference between 0.5-1.7), the electron cloud of the nonpolar atom (or molecule) is influenced and distorted, leading to the formation of temporary dipoles. As the polarity is induced (forced) in the otherwise nonpolar atom, the Debye forces are said to show an Induction effect.

Metallic solid consists of several metal atoms of the same kind bonded together closely. Due to their large size, metals easily lose their outermost valence electrons. The delocalized valence electron drifts and is now available for the other nuclei of metal atoms. Several delocalized electrons are comparable to a sea of electrons.

A molecule is said to be polar if the bond electrons between the atoms in a covalent bond are unequally distributed, creating two ends. The electron redistribution is marked by showing the separation of charges as a partial charge above the atom's symbol. Therefore, a polar molecule always has a positive and a negative end resulting in a dipole. The pulling of bond electrons by an atom is attributed to its electronegativity.

Keesom forces occur in polar molecules where the atoms have a considerable electronegativity difference, resulting in the charge separation and formation of positive and negative poles. The negative pole of one molecule electrostatically interacts with the positive pole of the neighboring molecule. Consequently, all the polar molecules in the medium try to orient their dipoles to be in alignment for such electrostatic interactions.