What does it mean for a chemical equation to be balanced? a) the number of atoms is the same for both the reactants and products. b) the number of each type of atom is the same for both the reactants and products. c) the number of different molecules has to be the same for both the reactants and products.

Determine the number o moles of ions/atoms/particle in the following: 2.50 miles of k2s (let me know how to do)

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

Which of these conditions most likely produces an unstable isotope?