Atomic Models Exercise

ATOMIC MODELS EXERCISE 1. Which of the following has a positive charge? (a) proton (b) neutron (c) anion (d) electron (e) atom 2. Rutherford carried out experiments in which a beam of alpha particles was directed at a thin piece of metal foil. From these experiments he concluded that: (a) electrons are massive particles. (b) the positively charged parts of atoms are moving about with a velocity approaching the speed of light. (c) the positively charged parts of atoms are extremely small and extremely heavy particles. (d) the diameter of an electron is approximately equal to that of the nucleus. (e) electrons travel in circular orbits around the nucleus. 3. Consider the species 72Zn, 75As and 74Ge. These species have: a) the same number of electrons. b) the same number of protons. c) the same number of neutrons. d) the same number of protons and neutrons. e) the same mass number. 4. The neutral atoms of all of the isotopes of the same element have (a) different numbers of protons. (b) equal numbers of neutrons. (c) the same number of electrons. (d) the same mass numbers. (e) the same masses. 5. The Heisenberg Principle states that _____________. a) no two electrons in the same atom can have the same set of four quantum numbers. b) two atoms of the same element must have the same number of protons. c) it is impossible to determine accurately both the position and momentum of an electron simultaneously. d) electrons of atoms in their ground states enter energetically equivalent sets of orbitals singly before they pair up in any orbital of the set. e) charged atoms (ions) must generate a magnetic field when they are in motion. 6. Which statement about the four quantum numbers which describe electrons in atoms is incorrect? a) n = principal quantum number, n = 1, 2, 3, ...... b) l = subsidiary (or azimuthal) quantum number, l = 1, 2, 3, ... , (n+1) c) ml = magnetic quantum number, ml = (-l), .... , 0, .... , (+l) d) ms = spin quantum number, ms = +1/2 or -1/2. e) The magnetic quantum number is related to the orientation of atomic orbitals in space. 7. Who discovered electron? a. Rutherford. b. J. J. Thomson. c. Neils Bohr. d. James Chadwick. 8. Who proposed the First atomic theory? a) John Dalton. b) Robert Millikan. c) J. J. Thomson. d) Neils Bohr. 9. The electronic configuration for oxygen is written as 1s2 2s2 2p4. Which rule will this configuration be violating? a) Aufbau’s principle. b) Hund’s rule. c) Pauli’s exclusion principle. d) None of the above. 10. Who of the following was awarded the Nobel Prize for his measurement of elementary electronic charge? a) Rutherford b) Robert Millikan c) James Chadwick d) JJ Thomson 11. How are the subshells in an atom labelled? a) s, p, d, f, g b) s, p, f, g, d c) s, f, g, d, f d) s, d, g, p, f 12. Atoms which have same mass number but different atomic number are called a) isotopes b) isomers c) isotones d) isobars 13. Experimentation with cathode ray led to the discovery of a) electron b) proton c) neutron d) nucleus 14. Atomic mass of an element is equal to a) mass of electron b) mass of neutron c) the sum of mass of proton and neutron d) the sum of mass of electron and proton 15. Who explained the behavior of positively charged particles being deflected from a metal fousceil as the nucleus a) Ernest Rutherford b) James Chadwick c) John Dalton d) Niels Bohr 16. In the gold foil experiment, most of the particles fired at the foil a) bounced back b) were absorbed by the foil c) passed through the foil d) combined at the foil 17. Which of the following statement is wrong about electron a) It is a particle b) Its motion is affected by magnetic field c) It has wave like property d) It emits energy while moving in orbit 18. The gold foil experiment led to the discovery of a) cathode ray b) electron c) neutron d) proton 19. Principle quantum number describes a) size of the orbital b) shape of the orbital c) spin of the orbital d) orientation of the orbital 20. Anode rays were discovered by a) Rutherford b) Goldstein c) J J Thomson d) J. Stoney