Question 107
The table shows some information about four elements. These elements are from the same group in the Periodic Table. They are given in the same order as in the Periodic Table.
| Element | Melting point in °C | Boiling point in °C | Reaction with water |
|---|---:|---:|---|
| lithium | 180 | 1342 | Gives off bubbles of gas and gives off heat |
| sodium | | 883 | |
| potassium | 63 | | Gives off gas and gives off so much heat that it catches fire |
| rubidium | 39 | 688 | Explodes with such force that the container cracks. |
The following are the mass numbers of the four elements in the table above: 23, 7, 39, 85. Match the numbers with the elements.
| Element | Melting point in °C | Boiling point in °C | Reaction with water |
|---|---:|---:|---|
| lithium | 180 | 1342 | Gives off bubbles of gas and gives off heat |
| sodium | | 883 | |
| potassium | 63 | | Gives off gas and gives off so much heat that it catches fire |
| rubidium | 39 | 688 | Explodes with such force that the container cracks. |
The following are the mass numbers of the four elements in the table above: 23, 7, 39, 85. Match the numbers with the elements.
