Zadanie 1d
Wzorowane na: Chemistry HL Paper 3, May 2023, TZ2, pytanie 1(d). 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-1f.
The atomic volume of an element is defined by the formula
The table gives the atomic volumes of the elements with atomic numbers 5 to 19, in the form in which each occurs at STP. For an element that is a gas, the value is the volume occupied by one mole of its atoms. Where an element has a second form at STP, the atomic volume of that form is given in the last column.
| Atomic number | Atomic volume / cm3 mol−1 | Second form at STP / cm3 mol−1 |
|---|---|---|
| 5 | 4.62 | n/a |
| 6 | 5.30 | 3.42 |
| 7 | 11 350 | n/a |
| 8 | 11 350 | 7 570 |
| 9 | 11 350 | n/a |
| 10 | 22 700 | n/a |
| 11 | 23.8 | n/a |
| 12 | 14.0 | n/a |
| 13 | 9.99 | n/a |
| 14 | 12.1 | n/a |
| 15 | 17.0 | 14.1 |
| 16 | 15.5 | 16.4 |
| 17 | 11 350 | n/a |
| 18 | 22 700 | n/a |
| 19 | 45.4 | n/a |
Polecenie
Explain the steady fall in atomic volume from element 11 to element 13.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
Any two of:
the «effective» nuclear charge/number of protons rises across the period ✔
more valence electrons are delocalized per atom «1, 2, 3» ✔
the attraction between the metal cations and the delocalized electrons grows, so the metallic bonding is stronger ✔
OR
the radius of the metal ions/atoms decreases ✔
Schemat punktowania
Any two of the four points, [2] max. The explanation must refer to the strength of the metallic bonding or to its causes, not only to the observation that the atoms are smaller.