Benchmark 4D
The Physical Setting: Structure of Matter
Grades 3-5, page 77

Materials may be composed of parts that are too small to be seen without magnification.

The most closely related standard is at a higher level of sophistication.

NSES Content Standard B 
Physical Science: Structure of atoms 
Grades 9-12, page 178 
Matter is made of minute particles called atoms, and atoms are composed of even smaller components. These components have measurable properties, such as mass and electrical charge. Each atom has a positively charged nucleus surrounded by negatively charged electrons. The electric force between the nucleus and electrons holds the atom together.