Question

chemistry resources
ionic compounds can be represented by bohr model diagrams and lewis dot structures. the valence electrons of a cation are not shown in its lewis dot structure.
bohr model of nacl
lewis dot structure of nacl
select the true statements.
a sodium cation has zero valence electrons.
valence electrons are shown in the bohr model of a sodium cation.
both the bohr model and the lewis dot structure represent an ionic bond between a metal and a nonmetal.
valence electrons are shown in the lewis dot structure of a chloride anion.

Explanation:

1. For the first statement: Sodium (Na) has an electron configuration of $1s^22s^22p^63s^1$. When it forms a cation ($Na^+$), it loses its single 3s valence electron, leaving it with 0 valence electrons.
2. For the second statement: The Bohr model of the sodium cation shows all remaining electrons (the full inner shells), but these are not valence electrons; valence electrons are the outermost shell electrons, which $Na^+$ no longer has, so this is false.
3. For the third statement: NaCl is formed from sodium (a metal) and chlorine (a nonmetal), and both models represent the ionic bond resulting from electron transfer, so this is true.
4. For the fourth statement: The Lewis dot structure of the chloride anion ($Cl^-$) shows 8 valence electrons (dots around the Cl symbol), which matches the structure provided, so this is true.

Answer:

A. A sodium cation has zero valence electrons.
C. Both the Bohr model and the Lewis dot structure represent an ionic bond between a metal and a nonmetal.
D. Valence electrons are shown in the Lewis dot structure of a chloride anion.