Final answer:
The solid type where particles do not form a regular pattern is an amorphous solid. Amorphous solids, like glass and plastics, have irregular, non-ordered internal structures.
Step-by-step explanation:
Types of solids can be generally categorized into two groups: crystalline solids and amorphous solids. Crystalline solids have a regular, repeating three-dimensional pattern, with classic examples including table salt (NaCl), which consists of an orderly array of Na+ and Cl- ions. On the other hand, the type of solid in which particles do not form a regular pattern is known as an amorphous solid. Materials like glass and many plastics are considered amorphous because they have long chains of molecules that do not exhibit any order from one molecule to the next and hence lack an ordered internal structure.
The correct answer to the question, "What type of solid's particles do not form a regular pattern?" is 1) Amorphous solid.