An element 'X' has a valency 3:

1. Write the chemical formula of its phosphide.
2. Write the chemical formula of its carbonate.
3. Is element 'X' a metal or non-metal?

"Please explain the answers also!"

phospide means a compound of the given element X  with P (- 3 )

therfore compound is : XP 

carbonate means a compound of the given element X with CO₃ (-2)

therefore compound is : X₂(CO₃)₃

The element X should be a metal . If a elemtn reacts with a metal it is a non-metal and vice versa. Since Carbon and Phosphorus are no-metals , X is a metal

I hope its right. Hope I helped