The Conceal atoms animation make atoms (and bonds between them) disappear progressively between two frames. This is done via the visibility of nodes and not via their transparency.
See also animations: Reveal atoms, Appear, Disappear, Flash, Pulse, Show, Shown, Hide, Hidden
First, choose atoms and bonds that you want to progressively disappear.
Then, double-click on the Conceal atoms animation effect in the Animation panel of the Animator.
This animation has 4 keyframes:
Move the keyframes of the animation as needed.
Note: You can always move the keyframes of the animation.
You can change how the parameters are interpolated between the frames by modifying the Easing curve.
Some examples of presentations available on SAMSON Connect - Documents that use this animation: