1.3 Ionic interactions between charged atoms can be very strong, but are attenuated by water

ion pair, salt bridge

The simplest kind of electrostatic interaction is between two atoms, or groups of atoms, each of which bears a full positive or full negative charge. When two oppositely charged groups are close to each other, the interaction is called an _____ ___ or a _____ ___

electron

one full charge corresponds to the magnitude of the charge on the ___

favorable, decreases, strongly, repulsions

the energy of interaction between two charges is described by Coulomb’s law. The energy becomes increasingly negative (that is, more _____) as the distance between two opposite charges _____. This causes two opposite charges to attract each other more ___ as they come closer. But, just as for the van der Waals interaction, when the atoms get very close, the energy starts to go up steeply because of electronic _____-.

ion pair

As you can see in Figure 1.9, the stabilization energy is much greater, and the attractive force makes the optimal distance smaller for an ___ ___ than for a van der Waals interaction (see Figure 1.8). The electrostatic attraction also falls off more slowly with increasing distance for it

strength, distance

Water and ions can weaken electrostatic interactions, reducing both their ____ and the _____ over which they operate. If the same two ions are separated by 3 Å in water, the interaction energy is reduced by a factor of 80, to about −6 kJ•mol−1

surface

Charged groups are typically found at the _____ of a protein, the interaction energy is lower because of water