Volcanic islands are created as a crustal plate moves over a

Magma hot spot.

Explanation:

Hot spots stay always the same location because they are in the mantle, not in the crust. So, that's why hotspots stay while plates are moving over them.

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).

a polar bond is formed when electrons are shared unevenly between atoms