Because the copper roofs, have been outside for a while and oxidization has occurred.
When metals become oxidized they rust, but when copper becomes oxidized, it turns greenish.
So copper roofs oxidize and turn green from being outside and a copper square doesn’t if it’s inside.
1077kjmol¹- + 498/2kjmol¹- + enthalpy=805*2kjmol¹- =1610-1319=291kjmol¹-
Answer:
B. Electrical charges of polar covalent bonds
Explanation:
Lewis structures, also known as Lewis dot diagrams are diagrams that show the bonding between atoms of a molecule and lone pairs of an electron that may exist in the molecule.
Polar covalent bonds are bonds that occur where a pair of electrons is shared unevenly between two atoms
The Lewis notation as an agreed convection, uses the delta sign to indicate polar covalent bonds when they occur in compounds. It shows that the electrons are shared unevenly.
Consider the example attached below. The Lewis structure for HF is given. the δ+ is used to show the electropositive Hydrogen atom while the δ- is used to show the electronegative Fluorine atom in the bond.