Zadanie 2c
Wzorowane na: Chemistry HL Paper 2, May 2026, TZ1, pytanie 2(c). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Informacja do zadań 2a-2e.
Rubidium, Rb, is a reactive metal.
Polecenie
(i) Write the equation for the reaction of Rb with water, H2O, including state symbols.
(ii) Describe the type of bonding in Rb and in H2O, and explain how the valence electrons in each produce that type of bond.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
(i) 2 Rb(s) + 2 H2O(l) → 2 RbOH(aq) + H2(g)
correct products and state symbols ✔
correct balancing ✔ «accept any correct multiples; accept the balanced ionic equation 2 Rb(s) + 2 H2O(l) → 2 Rb+(aq) + 2 OH−(aq) + H2(g)»
(ii) Rb: metallic bonding; the valence electrons are delocalized and attracted to the cations/positive ions «in the lattice» ✔
H2O: «polar» covalent bonding; the valence electrons are shared «unequally» between the atoms/nuclei ✔
Schemat punktowania
(i) [2] M1: correct products and correct state symbols; M2: correct balancing; award M2 only if the products are correct. (ii) [2] M1: Rb row correct (metallic bonding with delocalized electrons attracted to cations); M2: H2O row correct (covalent bonding with shared electrons). Award [1 max] for any single correct column (both bonding types named but no valid explanations). Do not accept protons or the nucleus in place of cations/positive ions.