C17 GROUP 7 - HALOGENS Flashcards
what is the test for chlorine and what colour does it turn?
- damp blue litmus paper
- blue, red, bleaches white
what is the product of chlorine and sodium?
sodium chloride
what is the product of hydrogen and a halogen?
hydrogen halide
what is the product of hydrogen and chlorine?
hydrogen chloride
what are some uses of chlorine
- disinfectants and bleaches
- treating water for drinking and swimming
- kills bacteria
why is group 7 reactive?
they want to gain 1 electron to have a stable outer shell
what is electronic configuration?
the arrangement of electrons in an atom
what happens to the atoms as you go down group 7?
- atoms get larger
- there are more shells and more shielding
-elements are less reactive - shorter half-life
what happens to colours of elements as you go down group 7?
colours get darker
explain the states of matter of the elements in group 7 at room temperature
higher in the group (i.e. fluorine and chlorine) = gas/liquid at room temperature
lower in the group (i.e. iodine)
= solid at room temperature
are group 7 elements diatomic molecules?
yes
what is a diatomic molecule?
molecules composed of two atoms
what colour is fluorine + state
pale yellow gas
what colour is chlorine + state
yellow/ green gas
what colour is bromine + state
red/brown liquid
what colour is iodine + state
grey/purple solid
what is the meaning of deposition?
changing state from a gas to a solid without being a liquid
what is the meaning of sublimation?
changing state from a solid to a a gas without being a liquid
why are halogens less reactive as you go down the group?
- halogens have 7 outer shell electrons, meaning they want to gain an electron
- as the distance between the nucleus and outer shell increases, there is less forces of attraction between the 2, meaning it is harder to gain another electron
- it is more difficult to form a negative ion
what is a displacement reaction?
when a more reactive element displaces (takes the place of) a less reactive element from its compound
what is the word equation for the reaction of lithium and iodine?
lithium iodide
(metal halide)
what is the word equation for the reaction of hydrogen and chlorine?
hydrogen chloride
(hydrogen halide)
what is formed when a hydrogen halide dissolves in water?
acidic solutions
hydrogen bromide dissolved in water = hydrobromic acid
what is sublimation?
to go from a solid to a gas without being a liquid
what is deposition?
to go from a gas to a solid without being a liquid
Why do halogens react readily with metals?
- halogens have seven electrons in their outer shell and need to gain one electron to become stable
- metals lose electrons easily, allowing them to form stable ionic compounds with halogens
What type of bonding is present in metal halides?
ionic
(metal transfers electron to a non-metal)
what is formed when hydrogen reacts with fluorine?
hydrogen fluoride
Why do halogens readily react with hydrogen?
they need to gain one electron to complete their outer shell
What is the name and colour of the only liquid halogen?
bromine and brown
What does chlorine look like?
pale green gas
How is iodine different to chlorine?
- solid and darker
-black in colour
Name the compound formed when hydrogen reacts with chlorine
hydrogen chloride
What is a displacement reaction?
when a more reactive element takes the place of a less reactive element from its compound
eg.
chlorine + sodium iodide -> iodine + sodium chloride
