What should be the ideal distance between keywords in Content? And, how much time it should be repeated in 300 to 500 words.
Your keyword density should be around 2-3%. I don't know of an ideal distance between keywords, but it should look naturally. Let it someone read and ask them what they think of the article.
Write naturally and don't worry about distance between keywords. And before posting your page on the internet, read it out loud to yourself. Does it sound stilted? contrived? clumsy? Then you're trying to write it for SEO (not recommended). When you read it out loud, it should flow nicely and sound pleasant to the ear.
I recommend you to put 3 keywords in such article. One is first 100 words, one in last 100 words and one in the middle.