Gas Giants And Black Holes

I was watching a program on the Science Channel and it ran you through the sequence leading to the creation of a black hole and it didn't quite add up for me.

The example was of a blue giant star with 1000x more mass than our own sun.

The sequence was roughly star runs out of hydrogen nuclei to fuse into helium --> fuses helium nuclei into heavier elements --> eventually fuses heavier and heavier nuclei all the way to iron --> fusion stops --> star collapses under gravity --> an explosion (supernova) ensues (and somewhere in all this, elements heavier than iron are formed) --> a black hole forms.

I guess I don't understand how / why a black hole forms only *after* there is a significant loss of mass due to a supernova explosion... if the mass left over after such an explosion is great enough to collapse into a singularity where not even light can escape, how is it not great enough to prevent the explosion in the first place?

Sorry if this is too elementary... my degree is in biological sciences, but I really love astrophysics (in my laymans' way) and this is bugging me.

Even though a significant mass from the outer-shell is ejected, there's more than adequate enough jobbies to pull the remainder into singularity mode.

After fusion stops, the core becomes INERT. That's an important consideration along with the amount of mass.

http://en.wikipedia.org/wiki/Type_II_supernova

Hard to imagine .... After fusion stops, the core becomes INERT.
Love my I report with sigh, hate my me to smile away, regardless head top what kind of the sky, I will greet the whole storm.

No, that's not what happens.

After fusion stops, there is not sufficient energy to prevent gravitational collapse. When that happens, there is further fusion, fueled by the energy of the gravitational collapse, which produces the elements above iron. The energy of the gravitational collapse fuels the supernova, which simultainiously blows the heavier elements into the universe, and implodes the remaining core into a black hole.

Just a short remark about black holes. I consider black holes as a pink unicorn of science. Its there and its black but no one can see it.