This means that they mixed .
I know for number 4 the answer is c, sorry I can't help with the others.
Answer:
The mass of the nucleus is almost the same as the atom because a majority of the mass of an atom is stored in the nucleus.
The volume of an atom is larger than the nucleus. The nucleus is a tiny, concentrated area inside of the atom. Atoms are mostly empty space inside.
Explanation:
Format Method - Writing the symbol of the cation and then the anion. Add whatever subscripts in order to balance the charges.
Crisscross Method - The numerical value of the charge of each ion is crossed over and becomes the subscripts for the other ion.