Zadanie 1a
Wzorowane na: Chemistry SL Paper 3, May 2023, TZ1, pytanie 1(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 1a, 1c-1f.
The table gives the first ionization energy and the first electron affinity of the elements in period 3 of the periodic table.
| Element | First ionization energy / kJ mol−1 | First electron affinity / kJ mol−1 |
|---|---|---|
| Na | 496 | −53 |
| Mg | 738 | +40 |
| Al | 578 | −42 |
| Si | 787 | −134 |
| P | 1012 | −72 |
| S | 1000 | −200 |
| Cl | 1251 | −349 |
| Ar | 1520 | +96 |
Polecenie
Outline why the first ionization energies of all the elements in the table are positive, whereas the first electron affinities of most of them are negative.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
ionization: energy is absorbed to overcome the attraction between the nucleus and the electron «being removed» AND electron affinity: energy is released as an attraction is established between the nucleus and the electron «being added» ✔
Schemat punktowania
Award [1] for both halves, each linked to energy absorbed/released and to the attraction between the nucleus and the electron. Accept "endothermic" for ionization and "exothermic" for electron affinity. Do not award for the sign convention alone.