B, titanium ion Ti3+ contains 19 electrons instead of 25 electrons, so item b is also wrong;
C, the number in the upper left corner of each square in the periodic table indicates the number of protons, and there are 22 protons in the titanium core. C is correct.
D, titanium is a kind of metal chemical formula that can only be expressed by element symbols, so item D is also wrong.
So choose C.