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Edexcel Jun 2015 (IAL) Paper 1 Q24
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![24 The diagram below shows the pattern in the first ionization energies of the first 18 elements. First ionization energy / kJ mol1 2500 2000 1500 1000 500 He Ne Ar Li Na 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Atomic number (Z) (a) Give the equation, including state symbols, for the first ionization energy of fluorine. *(b) Explain why there is a general increase in the first ionization energies from sodium to argon. (2) (3)24 *P44880A02428*<br />
(c) *(i) Explain why the first ionization energy of aluminium (Z = 13) is less than that of magnesium (Z = 12). (2)*(ii) Explain why the first ionization energy of sulfur (Z = 16) is less than that of phosphorus (Z = 15). (2)(d) The table below, which is incomplete, refers to the elements sodium to sulfur. Al Si Element Melting temperature Structure Electrical conductivity Na low Mg high giant high (i) Complete the melting temperature row by using only the words high or low. (ii) Complete the structure row by using only the words giant or molecular. (iii) Complete the electrical conductivity row by using only the words high or low. (2) (2) (1) *P44880A02528* 25 Turn over<br />
(e) In an experiment, 2.76 g of sodium completely reacted with water to form 500 cm3 of aqueous sodium hydroxide. 2Na(s) + 2H2O(l) (cid:111) 2NaOH(aq) + H2(g) (i) Calculate the number of moles of sodium that reacted. (ii) Calculate the maximum volume, in dm3, of hydrogen that can be formed at room temperature and pressure. [1 mol of any gas occupies 24 dm3 at room temperature and pressure.] (iii) Calculate the concentration, in mol dm3, of the sodium hydroxide solution, NaOH(aq), formed in the experiment. (1) (2) (2) (Total for Question 24 = 19 marks) TOTAL FOR SECTION B = 60 MARKS TOTAL FOR PAPER = 80 MARKS 26 *P44880A02628*<br />](https://learnah.org/wp-content/uploads/2018/08/l_smalljpgJune_2015_IAL_QP_-_Unit_1_Edexcel_Chemistry_A-level_24-0.jpg)
![Mark Mark Acceptable Answers Reject Electron affinity equation (0) overall Equations with F2(g) score (0) overall F(g)F+(g) + e() OR F(g)e()F+(g) Species (1) State symbols IGNORE Any state symbols on electrons (1) 2nd mark is dependent on the first NOTE: F(g) + e()F+(g) + 2e() Use of Fl max (1) Acceptable Answers Reject Shielding increases (0) for 2nd mark (1) (1) 1st mark: Number of protons increases / increasing nuclear charge / increasing effective nuclear charge IGNORE Just the atomic number increases 2nd mark: Same shielding / same number of (occupied) shells / electron removed from the same shell / atomic radius decreases 3rd mark: Greater (electrostatic) attraction between nucleus / protons and (outermost) electron (1) Question Number 24(a) Question Number 24*(b)<br />
Mark Reject Mention of 2p, no 1st mark NOTE First mark must refer to aluminium 2nd mark: at higher energy / further from the nucleus / (more) shielded (by 3s) OR Magnesium electron is at lower energy / closer to the nucleus / less shielded (1) IGNORE References to stability of 3s2 or full s- orbitals / full s sub-shell in Mg Acceptable Answers Question Number 24(c)*(i) For aluminium 1st mark: (Electron lost from) (3)p-subshell / (3)p-orbital ALLOW Correct electron configuration for Al: 1s22s22p63s23p1 or [Ne]3s23p1 or drawn as electrons-in- boxes (1)<br />
Acceptable Answers Question Number 24(c)*(ii) For sulfur Reject Mark 1st mark: (Electron lost from a) pair of electrons / an orbital with electrons (spin-) paired / a full (p) orbital ALLOW Mention of (3)p4 OR Correct electron configuration for S:1s22s22p63s23p4 or [Ne]3s23p4 or drawn as electrons-in- boxes (1) (1) 2nd mark: (increase in) repulsion (allows e to be removed more easily) If no correct reference to Sulfur, then allow one mark for P (atom) has half-filled p sub-shell / p3 (arrangement) is stable.<br />
Acceptable Answers Reject Mark Question Number 24(d)(i) (Al) (Si) (P) (S) high high low low Four correct (2) Three correct (1) Question Number 24(d)(ii) (Na) (Al) (Si) (P) (S) Acceptable Answers Reject Mark giant (giant) giant giant molecular molecular ALLOW giant molecular for Si ALLOW simple molecular for P and/or S Five correct (2) Four correct (1) Acceptable Answers Question Number 24(d)(iii) (Na) (Al) (Si) (P) (S) high (high) high X low low All four must be correct IGNORE Any word written over X in the Si box Reject Mark<br />
Question Number 24(e)(i) Acceptable Answers Question Number 24(e)(ii) Moles H2 =x mol Na (1) Reject Reject Mark Mark Acceptable Answers ( 2.76 ) = 0.12(0) (mol) 23.0 Volume H2 = 0.06(0) x 24 = 1.44 (dm3) (1) ALLOW ECF from moles of Na in (e)(i) ALLOW Both marks if answer given 1440 cm3 Correct answer, no working scores (2) NOTE: The following answers score (1) mark with or without working 2.88 (dm3) / 2880 cm3 5.76 (dm3) / 5760 cm3 However, check as 2.88 could score 2 as a TE of 0.24 mol from (e)(i) IGNORE SF except 1 SF<br />
Acceptable Answers Question Number 24(e)(iii) 1st mark: Moles NaOH = moles of Na (1) Can be implied by use of value from (e)(i) 2nd mark: ( 0.12 ) = 0.24(0) (mol dm3) 0.500 (1) ALLOW TE from moles of Na in (e)(i) Correct answer, no working scores (2) IGNORE SF except 1 SF NOTE: TE from first mark to second mark only if answer from (e)(i) has been used in some way e.g. answer to (e)(i)2 would not score mark 1, but could then be used to score mark 2 as a TE Mark Reject No 2nd mark if give wrong units, e.g mol/dm3 dm3/mol (Total for Question 24 = 19 marks) TOTAL FOR PAPER = 80 MARKS TOTAL FOR SECTION B = 60 MARKS<br />](https://learnah.org/wp-content/uploads/2018/08/June_2015_IAL_MS_-_Unit_1_Edexcel_Chemistry_A-level_24-0.jpg)
