IB Question 4

IB Question 4 - there is a large increase in ionic radius...

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IB Review Question #4 Name:David Tsai Here is a sample question on the subject of Periodicity from a previous IB Test. 1. The following table shows values that appear in the Data Booklet. Table 1 Covalent (atomic) radii / 10 –12 m N 0 F 70 66 58 Na Mg Al Si P S Cl 186 160 143 117 110 104 99 Table 2 Ionic radii/10 –12 m N 3– O 2– F 171 146 133 Na + Mg 2+ Al 3+ Si 4+ P 3– S 2– Cl 98 65 45 42 212 190 181 Explain why (i) the magnesium ion is much smaller than the magnesium atom. (2) The loss of 2 outer elctrons makes the whole atom smaller (3 shells become 2 shells). This increases the net attractive force. (ii)
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Unformatted text preview: there is a large increase in ionic radius from silicon to phosphorus. (2) Silicon ion loses one shell, making the atom smaller. Phorphorous gains a shell, making the atom bigger. Sodium ion and florine ion both have the same electron arrangement. But sodium ion has one more proton than the florine ion, making it more attrative and smaller than the florine ion. (iii) the ionic radius of Na + is less than that of F . (2) Type Your Answer Here (Total 6 marks) MNHS IB HL Chemistry 1...
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This document was uploaded on 10/22/2010.

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