Direction (Q. Nos. 12and 14) This sectionis based on statement I and S...
(Ip-bp) repulsion make it pyramidal.
Thus, Statement I and II both are correct but Statement II is not the correct explanation of Statement I.
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Direction (Q. Nos. 12and 14) This sectionis based on statement I and S...
Statement I : BF3 molecule is planar but NF3 is pyramidal.
Statement II : N atom is smaller than B.
The correct answer is option 'B', which states that both Statement I and Statement II are correct, but Statement II is not the correct explanation of Statement I. Let's analyze each statement individually and then discuss the relationship between them.
Statement I explanation:
BF3 molecule is planar because it follows the VSEPR (Valence Shell Electron Pair Repulsion) theory. According to this theory, the electron pairs around the central atom repel each other and try to get as far away as possible, resulting in a molecular shape that minimizes electron pair repulsion. In the case of BF3, the boron atom has three bonded pairs of electrons and no lone pair of electrons. The repulsion between these electron pairs causes them to arrange themselves in a trigonal planar geometry, resulting in a planar molecule.
NF3 molecule, on the other hand, is pyramidal because of the presence of a lone pair of electrons on the central nitrogen atom. The lone pair of electrons exerts greater repulsion compared to the bonded pairs of electrons, causing the molecular shape to deviate from the ideal tetrahedral arrangement. The three bonded pairs of electrons arrange themselves in a trigonal pyramid geometry, resulting in a pyramidal molecule.
Statement II explanation:
The statement says that the nitrogen atom is smaller than the boron atom. This is true because the atomic radius of nitrogen is smaller than that of boron. Atomic radius is defined as the distance between the nucleus of an atom and the outermost shell of electrons. As we move across a period in the periodic table from left to right, the atomic radius generally decreases. Nitrogen is located to the right of boron in the periodic table, so its atomic radius is smaller.
Relationship between Statement I and Statement II:
Statement II does not provide a direct explanation for why BF3 is planar and NF3 is pyramidal. The difference in molecular shape between these two molecules is primarily due to the presence or absence of a lone pair of electrons on the central atom rather than the size of the atom. The planarity of BF3 is a result of the absence of a lone pair, while the pyramidal shape of NF3 is a result of the presence of a lone pair. Therefore, while Statement II is true, it is not the correct explanation for the difference in molecular shape between BF3 and NF3.
Direction (Q. Nos. 12and 14) This sectionis based on statement I and S...
Nitrogen is smaller than boron.Wow what a chemistry
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