Which has larger dispersion forces

They can quickly run up smooth walls and across ceilings that have no toe-holds, and they do this without having suction cups or a sticky substance on their toes.

And while a gecko can lift its feet easily as it walks along a surface, if you attempt to pick it up, it sticks to the surface. How are geckos as well as spiders and some other insects able to do this? The huge numbers of spatulae on its setae provide a gecko, shown in [link] , with a large total surface area for sticking to a surface.

In , Kellar Autumn, who leads a multi-institutional gecko research team, found that geckos adhered equally well to both polar silicon dioxide and nonpolar gallium arsenide. This proved that geckos stick to surfaces because of dispersion forces—weak intermolecular attractions arising from temporary, synchronized charge distributions between adjacent molecules.

By curling and uncurling their toes, geckos can alternate between sticking and unsticking from a surface, and thus easily move across it. Further investigations may eventually lead to the development of better adhesives and other applications. There are two effects: a bigger atoms are more polarizable, and b bigger molecules have more electrons to polarize.

A iodine atom is bigger than a chlorine atom. Its valence electrons are much further from the nucleus, so they are not tightly held. A nearby dipole can distort the electron cloud of iodine much more than it can distort that of a smaller atom. An iodine molecule has much stronger London dispersion forces than a chlorine molecule. That's why, at room temperature, chlorine is a gas, bromine is a liquid, and iodine is a solid.

Even if the atoms are the same size, bigger molecules have stronger London dispersion forces. Related Questions Draw the major product s of electrophilic chlorination of p-cyanobenz Convert mL to the unit dm3. How many liters of water can be formed if 1.

What happens to energy during the formation of a solution? A measure of the strength of the LDFs will be the compounds' boiling point. The stronger the dispersion forces, the higher the boling point will be. If you take into account the two rules I've mentioned, you'll end up, in order of increasing boiling point , i.

Butane has two constitutional isomers called butane and isobutane. Butane is a straight-chain hydrocarbon, while isobutane is a branched-chain hydrocarbon. This is important to note because it offers an example on how surface area affects the strength of the LDFs. Because the branched-chain isomer has a smaller surface area, you could predict a lower boiling point when compared with straight-chain butane.