15. Which is NOT TRUE about atom? at is the building block of all matter b. it is composed of protons, electrons and neutrons c. It has a nucleus d. it cannot be divided into parts. 16. Which sub-atomie particle makes up most of the mass of the atom? proton b. neutran e electron 17. Me proposed the plum pudding model of the atom in which the negatively-charged les o notions embedded in a kind of cloud or soup of positive charge. # Thomson . Emest Rutherford e William Geiger och Dalton 18. The alpha particle scattering experiment led Rutherford's team to propose another model for the o nuclear model which is known as a plum pudding model b. raisin bread model planetary model 19. It is a sub-atomic partide that identifies the atoms of an element. a proton b. neutron c electron 20. Which of the following deseribes isotopa? atome having the same number of protons but different number of electrons b. atoms having the same number of protons but different number of neutrons c. atoms having different number of protons but the same number of electrons d. atoms having different number of protons but the same number neutrons