No, it's just that all hints for a word can be shown everywhere. So på can be translated as about in some other contexts (what comes to mind is Jag tänker på dig 'I am thinking of you') but not here.
If you want to say 'I write about Swedish', that would be Jag skriver om svenska:
There are actually many words with sch in Swedish, although we always use the pronunciation of e.g. "sh" in English.
I can't come up with any words that have an ij cluster, though - all excemptions are compounds where one syllable ends in i and the next begins in j, and of course that's not the same thing at all.
schack, schablon, schakal, schakt, schnitzel, schnauzer, schizofren, schottis, schäfer, schampo, schalottenlök, schweizisk, schema...
Those are just a small sample, and only words that start with sch.
I must amend what I said above, though. I wanted to make clear that we don't have the Dutch sch sound where the /s/ is followed by the /x/ - but a small number of loanwords use the /sk/ pronunciation, e.g. schizofren.
I don't think there are any. I tend to confuse similar sounding words. I cannot get my head round the Swedish 'leker' because in Dutch 'lekker' means 'tasty'. It's tiredness that does it. The best way is to work on each language every day and keep at it. The other day I managed to get a long French word wrong - I'd taken half a Swedish word and added half a Dutch word and in the process managed to mangle three languages...
Devalanteriel says that there are Swedish words with 'sch' . I hope he can give some examples, because I'm very curious about them. "Leker": I'm thinking of Lego to play with. Mixing languages: the Italian "gonna" sounds like the Dutch "japon", the chic word for dress, but it's skirt; and yes, I got it wrong once again. Yesterday I mixed Swedish with Italian: "una jacka" instead of "una giacca". The human brain has weird twists. What is your native language?