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Which has the strongest intermolecular forces iodine, chlorine, bromine and why?
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+ Chlorine
+ Physical chemistry
+ Intermolecular forces
+ Chemistry
+ Iodine
Posted by
Norman Pallas
Which has the strongest intermolecular forces iodine, chlorine, bromine and why?
Intermolecular forces can be most easily seen among the halogens by looking at the pure elements. All are diatomic molecules and as the molecular mass rises from chlorine, through bromine and iodine, the phases at room temperature change from a gas, to a liquid, to a solid, for each. The intermolecular forces increase as the melting point rises.
Intermolecular forces can be most easily seen among the halogens by looking at the pure elements. All are diatomic molecules and as the molecular mass rises from chlorine, through bromine and iodine, the phases at room temperature change from a gas, to a liquid, to a solid, for each. The intermolecular forces increase as the melting point rises.
Since all three of your choices are homonuclear diatomics (two atoms the same in a molecule), there is no polarity in the molecule so no dipole-dipole forces and no hydrogens so no H-bonding. The only type of intermolecular force possible is London Dispersion forces. These forces depend on the polarizability of the species. By that, I mean the ease with which the electrons can move around and create temporary dipoles in the other-wise non-polar molecule. The larger the species, the further away from the nucleus the outer electrons are and hence the less strongly they are held. This means the bigger atoms will be more polarizable. So, the order from biggest-smallest molecules (strongest to weakest IMF) is iodine, bromine and finally chlorine.
Edit: You can see the difference in the standard state of these three. Iodine is a solid at STP, Bromine is a liquid and Chlorine is a gas. The strongest forces hold the molecules together in a solid, the medium forces hold together enough to form a liquid and the weakest of them cannot hold them together at all so they remain a gas.
Since all three of your choices are homonuclear diatomics (two atoms the same in a molecule), there is no polarity in the molecule so no dipole-dipole forces and no hydrogens so no H-bonding. The only type of intermolecular force possible is London Dispersion forces. These forces depend on the polarizability of the species. By that, I mean the ease with which the electrons can move around and create temporary dipoles in the other-wise non-polar molecule. The larger the species, the further away from the nucleus the outer electrons are and hence the less strongly they are held. This means the bigger atoms will be more polarizable. So, the order from biggest-smallest molecules (strongest to weakest IMF) is iodine, bromine and finally chlorine.
Edit: You can see the difference in the standard state of these three. Iodine is a solid at STP, Bromine is a liquid and Chlorine is a gas. The strongest forces hold the molecules together in a solid, the medium forces hold together enough to form a liquid and the weakest of them cannot hold them together at all so they remain a gas.
Intermolecular forces can be most easily seen among the halogens by looking at the pure elements. All are diatomic molecules and as the molecular mass rises from chlorine, through bromine and iodine, the phases at room temperature change from a gas, to a liquid, to a solid, for each. The intermolecular forces increase as the melting point rises.
Intermolecular forces can be most easily seen among the halogens by looking at the pure elements. All are diatomic molecules and as the molecular mass rises from chlorine, through bromine and iodine, the phases at room temperature change from a gas, to a liquid, to a solid, for each. The intermolecular forces increase as the melting point rises.
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Since all three of your choices are homonuclear diatomics (two atoms the same in a molecule), there is no polarity in the molecule so no dipole-dipole forces and no hydrogens so no H-bonding. The only type of intermolecular force possible is London Dispersion forces. These forces depend on the polarizability of the species. By that, I mean the ease with which the electrons can move around and create temporary dipoles in the other-wise non-polar molecule. The larger the species, the further away from the nucleus the outer electrons are and hence the less strongly they are held. This means the bigger atoms will be more polarizable. So, the order from biggest-smallest molecules (strongest to weakest IMF) is iodine, bromine and finally chlorine.
Edit: You can see the difference in the standard state of these three. Iodine is a solid at STP, Bromine is a liquid and Chlorine is a gas. The strongest forces hold the molecules together in a solid, the medium forces hold together enough to form a liquid and the weakest of them cannot hold them together at all so they remain a gas.
Since all three of your choices are homonuclear diatomics (two atoms the same in a molecule), there is no polarity in the molecule so no dipole-dipole forces and no hydrogens so no H-bonding. The only type of intermolecular force possible is London Dispersion forces. These forces depend on the polarizability of the species. By that, I mean the ease with which the electrons can move around and create temporary dipoles in the other-wise non-polar molecule. The larger the species, the further away from the nucleus the outer electrons are and hence the less strongly they are held. This means the bigger atoms will be more polarizable. So, the order from biggest-smallest molecules (strongest to weakest IMF) is iodine, bromine and finally chlorine.
Edit: You can see the difference in the standard state of these three. Iodine is a solid at STP, Bromine is a liquid and Chlorine is a gas. The strongest forces hold the molecules together in a solid, the medium forces hold together enough to form a liquid and the weakest of them cannot hold them together at all so they remain a gas.
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