Answers to Practise Questions (Basic) – The Periodic Table Practise questions (Basic) are designed to ensure that students are aware of the basic concepts of the topic. This should be the first step that students undertake while revising for their chemistry examination. For the O Level examination, these basic concepts will be tested although questions will not be straight forward and students will need to be able to apply these concepts to solve the questions. (1): State what determine the group and period of an element The group of an element is determine by the number of outermost electrons and the period is determined by the number of shells the element has (2): State how is the periodic table arranged according to The period table is arranged according to the atomic number (proton number) of the element. (3): State three trends across a period Atomic radius decreases across a period Decrease in metallic properties and increase in non-metallic properties The oxide that is formed changes from basic to amphoteric to acidic. (4): State the change in oxides formed as we move across a period The oxides formed change from basic to amphoteric to acidic. (5): State the change in the structure of the element as we move across a period The structure of the element changes from metallic to giant molecular to simple ©Breeze Education 2015 breeze-education.com Page 1 molecular (6): State three properties of Group I metals, transition metals and Group 7 halogens. For Group I metals, (1): powerful reducing agents (2): low melting and boiling points (3): low densities (4): reactivity increases down the group For Group 7 halogens, (1): Powerful oxidizing agents (2): exists as diatomic molecules (3): Color becomes darker down the group (4): Reactivity decreases down the group For transition metals, (1): Form colored compound (2): Used as catalyst in a chemical reaction (3): Have variable oxidation states (7): State three trends of Group I metals and Group 7 halogens down the group For group I metals, reactivity and density increases down the group. Melting and boiling point decreases down the group. For group 7 metals, reactivity decreases down the group. The melting and boiling point increases down the group and the element gets darker down the group. (8): Explain why group I metal are powerful reducing agents and group 7 halogens powerful oxidizing agents ©Breeze Education 2015 breeze-education.com Page 2 Group I metals are powerful reducing agents as they lose their outermost electron readily to attain the stable electronic configuration of a noble gas. Group 7 halogens are powerful oxidizing agents as they gain one electron readily to attain the stable electronic configuration of a noble gas. About Breeze Education: Breeze Education offers chemistry tuition to O Level Students. Tuition classes are conducted in small group to facilitate active discussion and consultation. Chemistry is taught in a way to facilitate easy understanding of the topic. Students are also honed on their revision techniques so that they can improve faster over a shorter period of time. Tuition sessions are planned and taught by Dr Francis who has a PhD in Biomedical Science from National University of Singapore. Lesson is conducted in Yishun with direct bus connecting to Sembawang and Woodlands. ©Breeze Education 2015 breeze-education.com Page 3