within the principle of hard and soft acids and bases (hsab) which pair of metal ions and donor atom is best matched:

a.) is the correct answer.

explanation:

d eras and periods

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.

i'm on my way to history not a mistory.