why are elementary particles structureless?

Element ary particles are structure less because they are the smallest building blocks of matter and do not have any internal structure or sub atomic particles . They are the smallest particles that can be observed directly and are not made up of smaller particles . This is why they are often referred to as point - like particles . Additionally , the behavior of elementary particles is governed by the laws of quantum mechanics , which describe the wave - like behavior of particles at the atomic and sub atomic level . This means that the properties of elementary particles are not well - defined and can only be described prob abil istically . </s>