Yes, RESPONSIBILITY is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, S 1, P 3, O 1, N 1, S 1, I 1, B 3, I 1, L 1, I 1, T 1, Y 4.

Is it a valid word?

RESPONSIBILITY is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the social force that binds you to the courses of action demanded by that force; every opportunity, an obligation; every possession, a duty"- John D.Rockefeller Jr
the proper sphere or extent of your activities
a form of trustworthiness; the trait of being answerable to someone for something or being responsible for one's conduct