Diatonic and chromatic half steps (semitones)
A half step (semitone ) can be diatonic or chromatic, but a half step is always the half of a whole step (a semitone is always the half of a tone ).
Chromatic half steps (Chromatic semitones )
A half step (semitone ) is chromatic when the two notes names of the interval have the same name, example: C and C#
Diatonic half steps (Diatonic semitones )
A half step (semitone ) is diatonic when the two notes names of the interval have not the same name, example: D and Eb or E and F
The chromatic scale is a succession of twelve pitches, each separated by a half step (semitone ).
Here is a ascending chromatic scale played by an oboe:
Here is a descending chromatic scale played by a soprano recorder:
Here is a game to play with half steps (semitones ):
External links to learn more about :
1 - https://en.wikipedia.org/wiki/Diatonic_and_chromatic
2 - https://www.dolmetsch.com/musictheory11.htm