Halogens Flashcards
Who is the Russian scientist given credit for organising the periodic table?
Dimitri Mendelev. He organised them according to the atomic order and their properties.
What is in Group 1 of the Periodic table (PT)
Alkali Metals. Lithium (Li), Sodium (Na),Potassium (K), Rubidium (Rb), Caesium (Cs),Francium (Fr).
Why are they called Alkali Metals?
Because they turn water into an alkali
Which is the most reactive in Group 1?
Francium - too dangerous to test in the classroom. Remember the video clip of the exploding bathtub?
Which is the least reactive metal in Group 1?
Lithium.
The Halogens are listed in which group of the Periodic table?
Group 7
What does halogen mean?
…….means they form salts
What happens to the reactivity of the metals as you go down the group?
They become less reactive as you go down the group. Flourine is the most reactive and Astatine the least reactive.
What is the chemical symbols for the following:
Flourine (an extremely reactive gas), Chlorine (a poisonous gas),
Bromine (a poisonous liquid)
Iodine (a solid)
F2, Cl2, Br2, I2
What does diatomic mean?
It means it has 2 (di) molecules.
How does chlorine react with iron (wire wool)?
Reacts very quickly after a small amount of heating, burns vigorously with a bright yellow flame and Iron Chloride is produced.
How does Bromine react with iron? (wire wool)?
It burns less vigorously than Chlorine but still with a bright yellow light. Iron bromide is formed and bromine gas escapes.
How does Iodine react with iron (Wire wool)?
It burns after some time as it takes a lot of heating and the reaction is much slower. It still burns with a bright yellow light but less vigorously than Bromine. Iron iodide coats the wire wool (reddish brown in colour)
What is formed when halogens react with metals?
Salts (of which there are many!!)
Name one common salt produced by a halogen reaction.
NaCl…Soduim Chloride or common table salt (to put on your chips!!)
Name some uses for Chlorine.
Used to make plastics (PVC) water treatment to stop disease, refrigerants (CFC’s - harmful to the ozone layer though!)
Name some uses for Bromine.
It is extremely corrosive but is used in some drugs and pesticides.
Name some uses for Iodine.
It is essential in our diet to control thyroid disease and is added to table salt and drinking water, used for the manufacture of medicines and dyes.
What is a displacement reaction?
This means that the more reactive substance will DISPLACE the less reactive substance. e.g.
Flourine Sodium Bromide—>Sodium Flouride + Bromine
e.g.
Bromine+Sodium Flouride—-> No reaction (FLOURIDE MORE REACTIVE!!!!)
Which is the most reactive - chlorine, bromine or iodine?
Chlorine
Would flourine react with a solution of potassium chloride? Why?
Yes because flourine is the more reactive.
Which properties of the halogens suggest they are non-metals?
They have low melting and boiling points and they have weak molecular bonds.
What test could you do on iodine to prove it is a non-metal?
It would not conduct heat or electricity well so you could try passing a current through it and if it wont go through it is not a metal.
How many molecules do the halogens have?
2, they are diatomic
e.g
Cl-Cl, Br-Br, Fl-Fl, I-I.
