How many greek gods are there and what are there names?

There are 12 gods and goddesses

Well, First there's Zeus

~Zeus ( Zoos)

The god of gods, thunder, and most powerful god.

On the right of Zeus is his younger sister Hera who he mad his wife

~Hera (Hair-uh)

The goddess of marriage and child birth

Beside Hera sat her son Ares

~Ares (air-ezz)

The God of War

Next to Ares sat his brother Hephaestus

~Hephaestus (Heff-a-stus)

The god of of fire he also builds a lot of things.

And then Aphrodite the wife of Hephaetus even though Ares and Aphrodite have a thing going. Aphrodite just appeared out of the sea one day.

~Aphrodite (Afro- diyte)

Goddess of Love

on the other side of Zeus sits his son Hermes

~Hermes (her-meez)

the messanger of the gods and the god of mischief and theifs.

Okay, by now I have actually gone out of order so, whatever

There is also Poseidon one of zeus's brothers

~poseidon (po-side-on)

God of the seas

Then athena, the twins Apollo and Artimes, and Dionysus. All children of Zeus.

~Athena (Uh-theen-uh)

Goddes of battle stadegy and wisdom

~Apollo (uh-paul-oh)

God of the sun and music

~Artemis (art-uh-miss)

Goddess of the hunt

~Dionsysus (not really sure how to pronounce this one so I'm gonna say Die-naus-iss)

God of wine.

Zeus also has another brother who does not stay in Olympus, but in Tartarus (Hell)

~Hades

God of the underworld or hell

and last but not least there is the eldest god Hestia Zeus's older sister

~Hestia (Hey-sta)

Goddes of Fire

Hoped that helps :)