If by that you mean an exoskeleton, yes.
Yes
Two electrons are in the external shell of vanadium.
Not without a Qi compatible external iPhone shell.
Butterflies do not have external plates for support and protection. Their bodies are covered in delicate scales that give them their vibrant colors. Their wings are thin and fragile, designed for beauty and flight rather than protection.
A sea turtle has an external shell.
Butterflies reproduce by internal fertilization and not by external fertilization. Butterflies, like most insects, will then lay the eggs and wait for them to hatch.
No, they eat their own shell.
A crab has an external hard shell, and is an invertebrate.
Snails have a shell, but no spine. Butterflies have an exoskeleton, but no spine. The defining characteristic for all vertebrates is a spine, so neither snails or butterflies are vertebrates.
There are several differences. Beetles have a hard shell covering their wings. This is actually a modified wing that has turned into a shell. Butterflies have no shell, but they have four wings instead of the two that Beetles have. Beetles can be brightly colored, but not as brightly colored as some butterflies. Butterflies live on flower nectar. Beetles usually eat plant or animal matter.
The only extant cephalopod that produces an external shell is the chambered nautilus. The shells produced by squid and cuttlefish are internal.
A caterpillar that, when in metamorphosis, cocoon looks like a walnut shell.