I think is D A have a nice day
Good luck bye
7.8 g/cm3 because Mass/Volume=Density
Zn(NO3)2 + Cu will be the result of this single displacement (replacement) reaction :))
Calcium belongs to the alkaline earth metal group. Within a group, the melting point decreases from top to bottom. This is because the as the atomic radii increases the outer valence electrons are shielded by the inner electrons and experience a lower nuclear attraction. As a result the bonds can be broken easily which lowers their melting point.
The three elements below Calcium ib Group II A which have a lower melting point are: Strontium (Sr), Barium (Ba) and Radium (Ra)
