ACSBR 1 Atomic Structure - Assignment ANS

Anglo-Chinese School (Barker Road) A Methodist Institution Founded in 1886 CHEMISTRY DEPARTMENT OF SCIENCE Name: ANSWERS ( ) Class: SEC 3 ATOMIC STRUCTURE – ASSIGNMENT ALEX LEE/2010 PAGE 1 OF 5 PURE/COMBINED/N-LEVEL Multiple-Choice Questions [20 Marks] TOTAL SCORE / 30 Write in your selected answer for the multiple-choice questions in the boxes provided. 1 2 3 4 5 6 7 8 9 10 C D C A D A C B D C 11 12 13 14 15 16 17 18 19 20 D A D C D D C D D C 1. The nucleus of an atom contains A protons only. C protons and neutrons only. B electrons and protons only. D neutrons only. 2. The mass number of an atom or an ion can be calculated by A number of protons + electrons. C number of electrons + neutrons. B number of protons + nucleons. D number of nucleons. 3. Which one of the following statements is not correct? A All hydrogen atoms contain one proton. B A proton has the same mass as a neutron. C An electron is 1840 times heavier than a proton. D A proton has the same but opposite charge as an electron. 4. Which of the following statements is true for all neutral atoms? A number of protons = number of electrons B number of protons = number of neutrons C number of neutrons = number of electrons D number of neutrons = number of protons + electrons 5. The element, symbol E, is written as . Which of the following is correct? A The number of neutrons in the nucleus is Z. B There are A electrons in the nucleus. C There are (Z – A) electrons surrounding the nucleus. D There are A protons in the nucleus.

ALEX LEE/2010 PAGE 2 OF 5 6. An iodine atom has nucleon number 127 and proton number 53. The atom contains A 53 electrons B 53 neutrons C 74 electrons D 127 neutrons 7. Which of the following shows an isotope of sulfur with 16 protons and 18 neutrons? A B C D 8. The number of neutrons present in an atom of manganese represented as is A 25 B 30 C 55 D 75 9. The atoms P and S have the same number of A protons B nucleons C electrons D neutrons 10. Which element in the table has atoms each containing 24 neutrons? element atomic number mass number A 8 16 B 12 24 C 21 45 D 22 48 11. Which of the following nuclei contains 90 protons and 144 neutrons? A X B X C X D X 12. Which of the following atoms has fewer neutrons than protons in its nucleus? A He B Li C Be D B 13. The relative atomic mass of naturally occurring chlorine is not a w h o l e n u m b e r . T h e m o s t important reason for this is that A chlorine is radioactive. B the mass of the electrons has been included. C naturally occurring chlorine cannot be obtained pure. D chlorine is made up of more than one type of atom. 14. Identify the missing word in the sentence below. “The ……………… electron shell (energy level) is able to accommodate up to a maximum of 18 electrons, but is generall