Answer:
memory cells
Explanation:
The unscrambled words are white blood cells, memory cells, and antibodies. Memory cells is the correct answer, so that's what you'd write.
In the <em>trial structure</em> (1st image below), every atom has an octet.
Valence electrons = 20
Valence electrons available = 4 + 2 +10 = 16
The trial structure has 4 electrons too many. The actual structure must have <em>two double bonds or one triple bond.</em>
The second image shows two possible Lewis structures.
Nuclei is a common thing atoms have, along with protons and electrons.