Such components are periodically organised (8)
I believe the answer is:
elements
'such components' is the definition.
'elements' can be an answer for 'components' ('element' can be a synonym of 'component'). I am not sure about the 'such' bit.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for elements that I've seen before include "He and I are two" , "Essential parts or the weather" , "First principles of the weather" , "Parts of something or the weather" , "Basic principles of the weather" .)