(a) Complete the table.
| Atomic No | Element | Electronic configuration | Select element of the same group |
|---|---|---|---|
| 11 | Sodium | ............... | (Ca/N/K) |
| 15 | Phosphorus | ............... | (Al/N/C) |
| 16 | Sulphur | ............... | (F/Cl/O) |
| 9 | Fluorine | ............... | (Ca/Cl/K) |
(b) Classify the elements given in the table as metals and non-metals.
(c) To which group does sodium belong? Why is Hydrogen not considered while describing the elements of this group?
(a) The completed table is given below:
| Atomic No | Element | Electronic configuration | Select element of the same group |
|---|---|---|---|
| 11 | Sodium | 2, 8, 1 | K |
| 15 | Phosphorus | 2, 8, 5 | N |
| 16 | Sulphur | 2, 8, 6 | O |
| 9 | Fluorine | 2, 7 | Cl |
(b)
| Element | Metal/Non-metal |
|---|---|
| Sodium (Na) | Metal |
| Phosphorous (P) | Non-metal |
| Sulphur (S) | Non-metal |
| Fluorine (F) | Non-metal |
(c) Sodium belongs to group 1.
Position of hydrogen is not satisfactory. Hydrogen atom is very small in size and therefore many of its properties are different from group 1 elements (alkali metals). It is a gas at room temperature, while other elements of group 1 are solid metals. Secondly, it does not readily form cations, in most compounds, whereas group 1 metals readily form cations and form only ionic bonds. Due to these reasons Hydrogen is not considered while describing the elements of group 1.