Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

[EX Q]: Question: The total number of protons and neutorns in an atom is called what? Answer: mass number
[EX A]: The mass number is defined as the total number of protons and neutrons in an atom.

[EX Q]: Question: Four electron groups orient themselves into what shape that has four faces? Answer: tetrahedron
[EX A]: Four electron groups orient themselves in the shape of a tetrahedron.

[EX Q]: Question: What structure shows the bonding between atoms, with dots representing available electrons? Answer: lewis structure
[EX A]:
Draw the Lewis electron dot diagram for each substance. Double or triple bonds may be needed.