From the pie chart, the percentage of students placed in Mechanical is 28%, and in Civil is 17%. The difference in the percentage of students placed is:
\[
28\% - 17\% = 11\%.
\]
So, the difference in the number of students placed is \( 11\% \) of the total number of students (1035 students):
\[
\frac{11}{100} \times 1035 = 113.85 \, \text{students}.
\]
Thus, the difference in the number of placed students between Mechanical and Civil students is approximately 114 students.