Based on the crystal structure of metals versus ionic compounds why are brittleness and hardness not the same thing

Compare and contrast physical changes with chemical changes.

Explain that newton first law,second law and third law of motion?

What type of interaction occurs between the r groups of valine and isoleucine in a tertiary structure? view available hint(s) what type of interaction occurs between the r groups of valine and isoleucine in a tertiary structure? salt bridge disulfide bridge hydrogen bond hydrophobic interaction