Halogens Flashcards
(16 cards)
What colour is fluorine? Reactivity?
Pale yellow gas. Highly reactive.
What colour is chlorine? Is it poisonous? Reactivity?
Greenish gas. It is reactive. Is poisonous only in high concentrations.
What colour is bromine? Is it poisonous?
Red liquid. It gives off dense brown/orange poisonous fumes.
What colour is iodine? What colour can it become?
Shiny grey solid. Can sublime into purple gas.
Trend in melting/boiling point down group 7.
Increases down the group. Molecules get larger. Thus more electrons. Thus more VDW forces between the molecules. IMF get larger. Thus more energy is needed to break the forces.
Trend in electronegativity down group 7.
Decreases down the group. Down the group, atomic radii increases as the number of shells increases. Thus, the nucleus is less able to attract the bonding pair of electrons.
What is electronegativity?
Power of an atom to attract a pair of electrons in a covalent bond.
What is an oxidising agent?
Electron acceptor.
Trend for oxidising strength down group 7.
Decreases
Which halogens displace which halogens?
A halogen that is a strong oxidising agent will displace a halogen that has a lower oxidising power from one of its compounds.
What precipitate do fluorides form?
No precipitate.
What precipitate do bromides form?
Cream precipitate
What precipitate do iodides form?
Pale yellow precipitate
What is disproportionation?
A reaction where an element simultaneously oxidises and reduces.
What is chlorine used for?
Water treatment to kill bacteria. Treats drinking water. Treats swimming pool water.
What is NaCl and NaClO used for?
Bleach and to disinfect/kill bacteria.
