This question is about bromine (Br2\text{Br}_2Br2) and hydrogen bromide (HBr\text{HBr}HBr).
Bromine exists as simple molecules.
Draw a dot-and-cross diagram to show the arrangement of the outer-shell electrons in a bromine molecule (Br2\text{Br}_2Br2).
Explain why bromine has a relatively low boiling point.
The symbols for two isotopes of bromine are:
79Brand81Br ^{79}\text{Br} \quad \text{and} \quad ^{81}\text{Br} 79Brand81BrState what is meant by the term isotopes.
Complete the table to show the number of protons, neutrons, and electrons in each of these two isotopes of bromine.
| 79Br^{79}\text{Br}79Br | 81Br^{81}\text{Br}81Br | |
|---|---|---|
| number of protons | ||
| number of neutrons | ||
| number of electrons |
When hydrogen gas reacts with bromine vapour, hydrogen bromide gas is produced and heat energy is transferred to the surroundings.
State the name given to a reaction in which heat energy is transferred to the surroundings.
Write a chemical equation to represent the reaction that takes place when hydrogen reacts with bromine.
Describe a chemical test to show that the gas produced is hydrogen bromide.
Describe a physical test to show that a sample of water is pure.
