| A | B |
|---|
| In the periodic table | halogens are in group VII |
| Symbol for chlorine is | Cl |
| symbol for bromine is | Br |
| I is the symbol for | iodine |
| Chlorine physical state is | gas |
| bromine physical state is | liquid |
| iodine physical state is | solid |
| chlorine colour is | pale green |
| bromine colour is | dark red |
| iodine colour is | grey |
| fluorine colour should be | pale yellow |
| fluorine physical state should be | gas |
| Astatine colour should be | darker grey than iodine |
| astatine physical state should be | solid |
| Are they metals or non metals? | non metals |
| In group VII so electrons in outer shell | 7 |
| form ions with metals charge is | 1- |
| chlorine forms ions with metals formula is | Cl(-) |
| bromine ion is | Br(-) |
| iodine ion is | I(-) |
| they all exist as diatomic molecules formula of chlorine is | Cl2 (subscript 2) |
| When Na (2,8,1) reacts with Cl (2,8,7) | 1 e transferred from Na to outer shell of Cl |
| With other non metals they form covalent compounds | covalent compounds |
| covalent compounds are non conductors of electricity because they exist as | uncharged molecules |
| when chlorine combines with H(1e) | 1 pair of e is shared between them |
| Cl (2,8,7) & O (2,6) | 2 pairs of e shared between them |
| C (2,4) and Cl (2,8,7) | 4 pairs of e shared between them |
| Reactivity increases | up the group |
| fluorine is the | most reactive halogen |
| Cl2 added to KBr (aq) | Br2 is displaced |
| Cl2 added to KI (aq) | I2 is displaced |
| Cl2 & KBr (aq) Br2 is displaced because | chlorine more reactive than bromine |
| Cl2 & KI(aq) I2 is displaced because | chlorine more reactive than iodineine |
| Cl2 added to KF(aq) | no reaction |
| Cl2 & KF(aq) no reaction because | fluorine more reactive than chlorine |
| Cl2 & KBr products are | KCl & Br2 (subscript 2) |
| Cl2 & KI(aq) products are | KCl & I2 (subscript 2) |
| I2 & KAtproducts are KI & At2 because | iodine more reactive than astatine |
| formula of sodium astatide is | NaAt |
| Astatide ion would be | At(-) |
