Grammar JLPT Level N4 - Lesson 9

Structure of かな:

Sentence + かな

Details about かな:

Originally a mixture of the sentence ending particles か, and な, かな evolved over time to become its own (singular) sentence ending particle, which roughly translates as 'I wonder if (A)?'.
As it is a sentence ending particle, かな can be added to the end of almost any sentence.

あの人(ひと)が道(みち)の真(ま)ん中(なか)で倒(たお)れてるけど、大丈夫(だいじょうぶ)かな。
That person over there is laying collapsed in the middle of the street, but I wonder if they are okay.
このコンロにこの魚(さかな)が入(はい)るかな？
I wonder if the fish will fit in this stove.

Combining the meanings か and な, we can see where かな gets its original meaning. か presents questions (usually to other people), while な shows that a statement is related purely to the speaker's own thoughts/opinions. In this way, かな expresses that the speaker's own thoughts are being questioned.

かな