Chapter 8 Review

Sec 2 LSS Self Revision Review Chapter 8: Atoms and Molecules Name: __________________________ Class: ____________ Date: ____________ Section A: Multiple-Choice Questions (MCQs) – 3 marks 1 2 3 1 Which of the following represents a molecule of an element? A P B P2 C PQ D 2P 2 The ingredients of a carbonated drink are listed on the drink can below. Which of the following is not true about the substances listed in the table? A The atomic number of the carbon atom is the same in all the substances. B The carbon dioxide molecule has two types of elements. C The mass number of the carbon atom is different in each substance. D The sugar molecule contains the greatest number of atoms. chemical formula of the ingredients sugar C12H22O11 carbon dioxide CO2 carbonic acid H2CO3 caffeine C8H10N4O2 citric acid C6H8O7 15

Sec 2 LSS 3 An atom is electrically neutral because: A it is made up of sub-atomic particles which have no charges. B it has an equal number of positive and negative charges. C it contains both positive and negative charges in its nucleus. D it does not take part in any chemical reaction. Section B: Structured Questions – 5 marks 1 Circle TRUE if the following statements are true and circle FALSE if they are false. If the statement is false, rewrite the statement so that it becomes correct. (a) Atoms of an element have a unique number of protons. TRUE / FALSE Correct statement: ……………………………………………………………………………………………… (b) Each atom has at least a proton, a neutron and an electron. TRUE / FALSE Correct statement: ……………………………………………………………………………………………… (c) The electrons move around the nucleus in regions known as electron shells. TRUE / FALSE Correct statement: ……………………………………………………………………………………………… (d) Among the sub-atomic particles, protons contribute most to the mass of an atom. TRUE / FALSE Correct statement: ……………………………………………………………………………………………… (e) The nucleon number of an atom is the total number of protons and electrons in an atom. TRUE / FALSE Correct statement: ……………………………………………………………………………………………… [5]

Sec 2 LSS Section C: Free Response Questions – 7 marks 1 The diagram below shows a simplified structure of an atom. X and Y are sub-atomic particles found in the nucleus. Region Z contains electrons surrounding the nucleus. The atom is electrically neutral. (a) Using information from the diagram only, state the number of protons, electrons and neutrons found in the atom. Explain how you arrived at your answer. ……………………..……………………..……………………..…………………………... ……………………..……………………..……………………..…………………………... ……………………..……………………..