The electron dot structure for aluminum shows three dots spaced around the chemical symbol for aluminum (Al). What do the three dots represent?

The use of piers and beams to build a strong foundation for a house.

Vander waals forces are inter molecular bonds that exist within molecules of the same substance. a water molecule is made up of oxygen and hydrogen atoms which share electrons between each other. the vander waals forces are forces that exist between multitude of different  molecules of water. dipole dipole forces is the type of vander waals force that exist in water. the oxygen atom which is more electronegative pulls the shared electron closer to itself thus generating a partial negative charge while the hydrogen acquire a partial positive charge. these two different charges causes attraction to occur in water molecules.

The answer to your q the total mass is 73

What are the activitys?   sorry if this took your points : (