Answer: A different group of scientists using different methods.
D) Chlorine, Cl. Hope that helped
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.
V²+ = (B)
X³+ = (D)
Y³- = (C)
Z²- = (A)
When an element loses electrons, the element gains a positive charge
When an element gains electrons, the element gains a negative charge
NOTE: Electrons are negative charges
