Number of paramagnetic ions among the following d- and f-block metal ions is ________.
\( \text{Mn}^{2+}, \text{Cu}^{2+}, \text{Zn}^{2+}, \text{Yb}^{2+}, \text{Sc}^{3+}, \text{La}^{3+}, \text{Gd}^{3+}, \text{Lu}^{3+}, \text{Ti}^{4+}, \text{Ce}^{4+} \).
(Atomic number of Mn \( = 25 \), Cu \( = 29 \), Zn \( = 30 \), Yb \( = 70 \), Sc \( = 21 \), La \( = 57 \), Gd \( = 64 \), Lu \( = 71 \), Ti \( = 22 \), Ce \( = 58 \))
