Zadanie 2a
Wzorowane na: Chemistry HL Paper 2, May 2026, TZ1, pytanie 2(a). 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) State the number of protons, electrons and neutrons in .
(ii) State the full electron configuration for .
(iii) The relative atomic mass, Ar, of Rb is 85.47.
| Isotope | Mass | Percent abundance |
|---|---|---|
| 72.17 % | ||
| 86.91 | 27.83 % |
Determine the relative mass of the first isotope of Rb to four significant figures, showing your work.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz CKE i punktacja
Odpowiedź z klucza
(i) Protons: 37; Electrons: 36; Neutrons: 48 ✔ ✔ «[2] for three correct answers, [1] for two»
(ii) 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 ✔
(iii) 85.47 = x(0.7217) + 86.91(0.2783) ✔
✔
Schemat punktowania
(i) [2] award [2] for three correct answers, [1] for two correct answers. (ii) [1] full configuration up to 4p with correct superscripts; ignore 5s0; the noble-gas core [Kr] is not accepted because the full configuration is asked for. (iii) [2] M1: weighted-average equation set up from the data; do not award M1 without working; M2: x = 84.91, which must be given to four significant figures. Other valid methods are allowed.