fourth period
The third period is similar to the second, except the 3s and 3p sublevels are being filled. Because the 3d sublevel does not fill until after the 4s sublevel, the fourth period contains 18 elements, due to the 10 additional electrons that can be accommodated by the 3d orbitals.
If we are talking about moles then the answer to that is 0.22
2nd one bhutdsaadxjytwwdghurfc
Based on the given conditions, the gravitational force acted on the body is greater than the force upward by a quantity equal to 500 N. Therefore, the net force will cancel out and will remain an amount of 500N downward relative to the gravitational force exerted by the object.