A pentahalide or a trihalide represents an element of group 15 with five or three halogen atoms. An element must either share electrons by covalent bonding with the halogens or lose electrons and ionic bond with the halogens to form a pentahalide or a trihalide.
All atoms and molecules show London Dispersion Force, a primary way atoms and molecules interact. Most of the time, molecules have additional stronger forces than the London Dispersion Force, which is the weakest. Therefore, London Dispersion forces are exclusively seen in the nonpolar molecules since they don't have other competing functional groups leading to other interfering intermolecular interactions.
Debye intermolecular forces of attraction occur between polar and nonpolar atoms or molecules.
When a polar molecule is in the vicinity of a nonpolar molecule, the electronegative end of that polar molecule attracts the electron cloud of the adjacent nonpolar molecule, thereby distorting it and inducing a pole separation. So, the polar molecule is said to have induced polarity in the neighboring nonpolar molecule.
The van der Waal forces of interactions are weak intermolecular forces. For the atoms or molecules show these interactions only under certain conditions -
1) Distance- van der Waal forces mainly depend on the distance between the associated molecules. These forces become very weak if the distance between the molecules or atoms is greater. These forces are relatively stronger if the atoms or molecules are grouped closely.
- The unit cells that makes up the entire crystalline solid has a fixed value for the length of the edges and the angle between the edges.
- Therefore, the heat energy required to melt a crystalline solid would have a fixed value.
Did you know that, back in the 1900s, it was believed that a hook and a loop type of closure was the covalent bond responsible for holding atoms in a molecule? Interesting, right?
The atoms or group of atoms are classified based on the Inductive effect as electron-withdrawing (-I) or electron-donating (+I) relative to Hydrogen.
The common functional groups showing +I and -I effect are:
+I group | -I group |
|---|---|
O- |
A nonpolar molecule is made of two or more atoms where the electronegativity difference between the atoms is less than 0.5. Therefore, the electron density in the bond is equally distributed, and there is no concentration of electrons on one atom to create a charge separation rendering the molecule essentially without poles or nonpolar. Such nonpolar molecules like H2, CH4, He, etc., will interact using the London dispersion forces without forming any positive or negative pole.
The longest carbon chain is the parent chain containing the principal functional group.
The principle functional group is always given the highest priority, lowest number (1 before 2, 3, 4...), and assigned as a suffix while writing the nomenclature. Therefore, the numbering of the parent chain always starts from the principal functional group.