What's an ideograph? Also, what's a radical? Are they the same thing?
Some radicals (in the Han script) may be ideographs, but most ideographs are not radicals: they often (not always) combine 1 or more radicals, with 1 or more strokes that are not radicals themselves.
Radicals in the Han script serve to their classification, and help users to locate ideographs in dictionnaries, but they also consider the additional strokes (radicals are themselves made of a wellknown number of strokes).
Ideographs rarely represent alone a concept or word, but most often a single syllable. In Chinese many words are short and consist in 2 syllables, and so are written with two ideographs.
We should call these characters "syllabographs" instead of "ideographs", but this may conflict with the concept of "syllabaries" that are much simpler, unlike Han ideographs that can each represent very complex syllables (with diphtongs, multiple consonnants, and distinctive tones), and sometime (in fact rarely) a concept or word (which may spelled with more than one syllable, depending on local dialects).
Many words are created from two ideographs, and the concept behind each ideograph is unrelated or sometimes very far to the meaning of the whole word. In that case, the pair of ideographs is chosen mostly because the concepts are pronounced similarly in some dialect of Chinese (sometimes old dialects), and so they can be read phonetically (For example, "Beijing" is written with the two ideographs for "bei" and "jing", but you may wonder why "bei" and "jing" were used, and which concepts they represent, and their relation to the name of the city...).
For these reasons, some linguists prefer to speak about "sinographs" (reference to Chinese), or sometimes "pictographs" (because of their visual form, instead of their meaning)...
