Easy molecular geometry

As a clarification: @ 2:56 = I say 360 / 4 = 109.5. I should have said 360/4 in 3D space is 109.5. Let me explain. Our goal is to create a central molecule with 4 electron groups evenly spaced around it. Since electrons repel each other, we will want to space those 4 electron groups as far apart as we can. On paper, if we were to draw this, we would space them 90* apart. Another example of this would be electrons would be placed at 12 oclock, 3 oclock, 6 oclock, and 9 oclock, so the 4 groups are about as far apart as possible. HOWEVER.... since molecules exist in 3D space, electrons can use the X, Y, and Z axis. Therefore, electrons can be spaced out a little further... not all lined up on one plane. So, electrons can spread out a little further, and the MAXIMUM distance between 4 evenly spaced electron groups in space would be 109.5. Sorry for the confusion!!!