Answer:
open system
Explanation:
An open system is a system in which both energy and matter are exchanged with the surroundings.
Answer:
they have differnet properties that repeat across the next period
Explanation:
Answer:
Hello!
Gold is a chemical element with symbol Au (from Latin: aurum) and atomic number 79. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal and a group 11 element.
So in short, the Correct Answer will be (D) an Element.
Hope that Helps! Have A Wonderful Day! ☺
Explanation: