Chemistry · Oct / Nov 2025 · Paper 41 · Question 2
0620
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The question as text
Calcium is an element in Group II of the Periodic Table.
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2(a)[1]
strontium / Sr
2(b)[4]
M1 metallic
M2 positive ions / cations
M3 sea of electrons / mobile electrons / delocalised electrons
M4 attraction between positive ions and electrons
2(c)(i)[3]
M1 effervescence
M2 solid dissolves
M3 solution turns blue
2(c)(ii)[2]
calcium hydroxide (1)
hydrogen (1)
2(d)(i)[1]
orange-red
2(d)(ii)[2]
2Ca + O2 → 2CaO
M1 CaO as only product
M2 correct equation
2(e)(i)[1]
water(s) of crystallisation
2(e)(ii)[3]
M1 3.28 ‣ 164 = 0.02(00)
M2 1.44 ‣ 18 = 0.08(00)
M3 = M2 ‣ M1 = 4
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