Chemistry, 02.07.2019 17:00, diamondscott9297

Would you expect any deviations from the expected bond angle in the chlorotrioxyl (clo3+) cation?

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No. Unlike perchlorate ions, the central chlorine atom in a $\text{ClO}_{3}^{+}$ ion contains no lone pairs. Additionally, that chlorine atom has three electron domains. It would therefore demonstrate a trigonometric planar geometry, with a bond angle of 120 degrees.

Bond angles might deviate from values expected from the number of electron domains due to the presence of lone pairs of electrons.

Both lone pairs and bonding pairs of electrons counts towards the number of electron domains around an atom. Lone pairs, however, do not take part in bonding.

Bond angles are predicted from the number of electron domains around an atom via the VSEPR theory. One key assumption of such predictions is that all pairs repel each other equally. This assumption might be true for most bonding pairs but not for the non-bonding lone electron pairs. Lone pairs of electrons repel other electron domains stronger than bonding pairs do. They would therefore squeeze bonding pairs into each other.

Bond angles measure the separation between atoms, which are connected to the central atom via one or more bonding pairs. Bond angles would therefore be smaller in molecules with lone pairs of electrons than in ones with an identical molecular geometry but fewer or no lone pairs.

Start by deducing the number of bonding pairs among all electron in the central chlorine atom.

A neutral chlorine atom contains 7 valence electrons. It would demand 1 more to achieve an octet (i.e. a complete valence shell, typically of eight electrons.) A neutral oxygen atom contains 6 valence electrons. It would demand 2 more to achieve an octet. A positive charge on the ion indicates the loss of one electron. In total, the four atoms in this polyatomic ion would take 1 more electron to achieve octets than they would do in a neutral molecule.

The $\text{ClO}_{3}^{+}$ ion would therefore demand $1 + 3 \times 2 + 1 = 8$ electrons to ensure an octet for each of its atom. Atoms in this polyatomic ion, $\text{ClO}_{3}^{+}$ would form 8/2 = 4 covalent bonds to fill the gap. Assuming that the chlorine atom is the central atom for having the weakest hold on valence electrons (i.e. electronegativity.) It would allocate the four bonds as two $\text{Cl}-\text{O}$ single bonds and one $\text{Cl}=\text{O}$ double bond with each of the three oxygen atoms. It might as well end up forming a resonance structure with the double bond as in carbonate $\text{CO}_3^{2-}$ ions.

The central chlorine atom now has, in its electron cloud, eight electrons from the four covalent bonds. It has hence achieved an octet without bonding to any lone pairs of electrons. The double bond counts as a single domain as each single bond does. Similar to carbonate ions (again,) with three electron domains and no lone pairs on the central atom, $\text{ClO}_{3}^{+}$ would demonstrate a trigonometric planar geometric with a O-Cl-O bond angle of 120 degrees.

answered: Guest

a is the answer to this question

explanation:

answered: Guest

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