According to the Valence Shell Electron Pair Repulsion Theory (VSEPR), the repulsion between electron pairs in the valence shell of an atom determines the shape of a molecule. In this theory, it is important to understand that lone pairs of electrons experience greater repulsion than bonding pairs.
Lone pairs are electron pairs that are not involved in bonding. These lone pairs are localized on one atom and are held more tightly by the nucleus of that atom, which makes them occupy more space. As a result, lone pairs repel each other more strongly than bonding pairs.
The order of repulsion strength according to VSEPR theory is:
lone pair-lone pair>lone pair-bond pair>bond pair-bond pair
In summary, lone pairs occupy more space due to their stronger attraction to the nucleus, which leads to greater repulsion compared to bonding pairs.
Resonance in X$_2$Y can be represented as
The enthalpy of formation of X$_2$Y is 80 kJ mol$^{-1}$, and the magnitude of resonance energy of X$_2$Y is:
Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): A typical unfertilized, angiosperm embryo sac at maturity is 8-nucleate and 7-celled.
Reason (R): The egg apparatus has 2 polar nuclei.
In the light of the above statements, choose the correct answer from the options given below:
Such a group of atoms is called a molecule. Obviously, there must be some force that holds these constituent atoms together in the molecules. The attractive force which holds various constituents (atoms, ions, etc.) together in different chemical species is called a chemical bond.
There are 4 types of chemical bonds which are formed by atoms or molecules to yield compounds.