1.matter is made up of small particles
2.particles of matter are in constant random motion
Explanation:
1.Particles eg of salt can be crashed into smaller particles 2.When you sprinkle pollen grains on water in a beaker and observe using a hand lens U'll see they are moving randomly
I think you might find your answer here https://answers.yahoo.com/question/index?qid=20121101101721AAeZyHE
The one with the largest atomic radius is barium
Hoped this helped:)