Question

there are a number of online periodic tables that you can use. one that is particularly useful is called ptable. with ptable you can hover over a class name like \metals\ and see the corresponding elements isolated and highlighted. this is a great way to become familiar with the various classes of elements. for instance, hovering over
onmetal\ isolates this class of elements and highlights them in green. for each of the following elements, indicate how they are classified. hydrogen (h) nonmetal sodium (na) choose calcium (ca) choose copper (cu) alkali metal silicon (si) metalloid

Explanation:

Based on the general classification of elements in chemistry, sodium (Na) is an alkali - metal, calcium (Ca) is an alkaline - earth metal, and copper (Cu) is a transition metal.

Answer:

Sodium (Na): Alkali metal
Calcium (Ca): Alkaline - earth metal
Copper (Cu): Transition metal