Questions de papier passé sur le tableau périodique

Study Notes

Past Paper Questions on the Periodic Table

Q5 (a): The periodic table can be used to answer questions about the development of the periodic table.
Q5(a)(i): One piece of evidence supporting Newlands' ideas is the repeating pattern of elements with similar properties every eighth element in the modern periodic table.
Q5(a)(ii): Two reasons why many chemists in 1866 didn't accept Newlands' ideas are: Newlands' table didn't accurately predict the behavior of undiscovered elements and the placement of some elements (such as iron) didn't fit the periodic patterns.
Q5(b): Chlorine, bromine and iodine are in Group 7. A student investigated the reactivity of these elements with various compounds.
Q5(b)(i): Reactivity trend for Group 7: Their reactivity decreases down the group. Chlorine is more reactive than bromine and bromine is more reactive than iodine. This is related to the increasing size of the atom down the group, which weakens the attraction to bonding pair of electrons.
Q5(b)(ii): The balanced equation for the reaction between chlorine and potassium bromide is: Cl₂ + 2KBr → 2KCl + Br₂.
Q6: The question focuses on John Newlands' early periodic table and the organization of elements.
Q6(a): Iron (Fe) doesn't fit the pattern in column 7 because its properties don't completely align with the adjacent elements.
Q6(b): The question describes how Mendeleev arranged the elements in periods and groups based on their weight.
Q6(c): Lithium, sodium and potassium are in Group 1 due to similar electronic structures, specifically, one electron in their outer shells.
Q7: The question deals with the halogens (Group 7) and their properties.
Q7(a): Boiling points of halogens increase down the group from fluorine to iodine.
Q7(b)(i): The symbols for ions in sodium bromide are Na⁺ and Br⁻
Q7(b)(ii): Chlorine reacts with sodium bromide solution to produce bromine and sodium chloride: Cl₂ + 2NaBr → 2NaCl + Br₂.
Q8: This question is about atomic structure and elements.
Q8(a)(i): The atomic number of an atom is the number of protons.
Q8(a)(ii): The mass number of an atom is the sum of protons and neutrons.
Q8(b): An atom has no overall charge because the positive charge of the protons is equal to the negative charge of the electrons
Q8(c): Fluorine and chlorine are in the same group due to having the same number of electrons in their outer shell.
Q8(iv): Suggesting which halogen could react with sodium chloride to produce chlorine is contingent on knowing the reactivity series and electron configurations.