Un muelle cuya constante elástica vale 150 N/m tiene una longitud de 35 cm cuando no se aplica ninguna fuerza sobre él. Calcula la fuerza que debe ejercerse sobre el muelle para que su longitud sea de 45 cm

1)each group 16 element has how many valence electrons? ( )4 ( )6 ( )8 ( )16 2)how many dots appear in the dot structure for calcium ion, ca2+? ( )zero ( )one ( )two ( )eight 3) which of the following atoms forms a cation to obtain an octet of outer shell electrons? ( )magnesium ( )oxygen ( )fluorine ( )helium 4) an al3+ ion contains 13 protons and 10 electrons. ( )true ( )false 5) valence and non-valence electrons are represented in lewis dot structures. ( )true ( )false

Ineed to find the answer of this question because i dont understand it

Draw the lewis dot structure for each of the following polyatomic ions