* Are attracted to negatively charged surfaces

* Tend to accumulate at the interface between a positively charged surface and a liquid

* Can form a positively charged layer at the interface, which can repel other positively charged ions and attract negatively charged ions

* Can increase the surface tension of a liquid

* Can promote the formation of emulsions and foams

Negatively charged ions (anions)

* Are attracted to positively charged surfaces

* Tend to accumulate at the interface between a negatively charged surface and a liquid

* Can form a negatively charged layer at the interface, which can repel other negatively charged ions and attract positively charged ions

* Can decrease the surface tension of a liquid

* Can inhibit the formation of emulsions and foams

The behavior of charged ions at interfaces is important in many areas of science and technology, including colloid science, surface chemistry, and electrochemistry.