I can't find the physical/math connection, b)?

The chemical bond types are simple

A)

Si- must be covalent

Csf-ionic

Ne- stable (I would put it this way)

Cu-metallic

…bond.

B)I usually know such diagrams with the energy level occupancy and not as a charge density distribution of the valence electrons.

Question 1: Is the charge density distribution higher at c than at b, and at b it is also lower than at d, and at a it is constant. Think about it: the smaller the period, the larger the charge density distribution.

2nd question: Why are frequencies shown exactly at this point? P.S. I know electrons are waves. But what does it mean here?

3. Isn't the position of the atoms different? I don't really understand what the dots are supposed to represent?

4. GUESS: Since neon doesn't react, A fits; the density can't change here. C is definitely ionic, with stronger attractive forces and higher density. I'm having trouble classifying B and D. The charge density distribution in the metal must be irregular, right?