Question

Which of the followin applies to Lewis dot structures ? Select all that apply.

a
the number of dots represent the number of valence electrons or their A-group number.
b
The number of dots represent the number of valence electrons in the last sub shells filled.
c
An atom can have 1 to 18 electrons placed around the element symbol - this is the case for period 4 elements.
d
An atom can have 1 to 8 electrons placed around the element symbol.

Answer 1

Correct answers: a, b and d.

- a is true: Lewis dots show the number of valence electrons (for main‑group elements this equals the A‑group number).
- b is essentially true: the dots represent the valence electrons in the outermost (last) subshells (what is being counted as "valence").
- d is true for the usual Lewis‑dot convention for main‑group elements (you place from 1 up to 8 electrons around the symbol — H/He exceptions: 1 or 2).
- c is false: you do not place up to 18 dots. Although heavier elements can have expanded octets (period 3 and below may accommodate more than 8 in bonding), Lewis dots still represent valence electrons, not all 18 inner/outer shell electrons.