2 is not a square because a trapezoid does have 4 sides, but the sides are not parallel, or congruent. ↓
4 is not a square because similar to the trapezoid, it does have 4 sides, but is not parallel nor congruent. ↓
Although some people consider a rectangle a square, it is a square and also is not because it has 2 pairs of parallel sides, instead of all 4 sides being parallel.
