The model to show what the difference are in the rod is shown in the second and last image attached
In the image attached, a charged rod is touching a metal ball. The leaves of the electroscope are moving further apart, indicating that the ball is becoming charged.
The charged rod induces an opposite charge on the surface of the metal ball. When the charged rod touches the metal ball, some electrons are transferred from the rod to the ball.
So, as a result of these interactions, the metal ball becomes negatively charged. The leaves of the electroscope move further apart because they are also negatively charged.