Zadanie 6b
Wzorowane na: Chemistry SL Paper 2, May 2024, TZ1, pytanie 6(b). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
Chromium is a first-row transition element.
(i) Deduce the nuclear symbol, ZAX, of the chromium-52 ion that contains 21 electrons.
(ii) Chromium(II) chloride, CrCl2, melts at 824 °C. Explain how the ions are held together in solid chromium(II) chloride and why the compound conducts electricity when molten but not when solid.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
(i) 2452Cr3+ ✔
(ii) electrostatic attraction between oppositely charged ions «Cr2+ and Cl−, in a lattice» ✔
in the solid the ions are held in fixed positions in the lattice and cannot move OR when molten the ions are free to move and carry the charge ✔
Schemat punktowania
(i) [1]; the charge must be shown. (ii) M1: electrostatic attraction between oppositely charged ions; do not accept only "ionic bonding". M2: the ions, not electrons, are mobile only when molten; accept "delocalized ions" but not "delocalized electrons".