1) Yes Carol, I don't know that the term is correct but that is what I meant with the piano. I would also apply it to other instruments e.g. it is possible to play in G on a D whistle but the natural scale to me would be the one where you block all holes and simple remove one finger at a time to get the next note which on a D whistle gives you Dmajor.

2) No Carol, as long as all the notes are there, the instrument is chromatic. It is just possible to use 2 diatonic scales to make a chromatic scale.

To confuse matters further, there are some oddballs like my Hohner Erica D/G melodeon where the first buttons on each row (stupid place to put them) provide the missing notes in the chromatic scale between my lowest G and the next G on the G row but do not cover the full range of the instrument...

Jon