An element at room temperature was found to have a metallic luster and brittle but a poor conductor of electricity and heat. Is it a semimetal, a nonmetal, or a metal?

Is element Y a metal or a nonmetal if its reaction with element X results in a product containing X³⁻ and Y²⁺ ions? Explain.

Classify the following as metal or nonmetal.

a. Na
b. Br
c. N
d. Ca