How can you tell a cu(no3)2 solution from a ni(no3)2 solution?

solution has blue color and solution has bright green color.

Explanation:

in its aqueous solution gives blue color solution. Copper being transition metal and gives characteristic color in their in aqueous solution.

in its aqueous solution gives bright green color solution. Nickel is also a transition metal and gives characteristic color in their in aqueous solution.

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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~ trueboss72