3.1.2 + 3.1.3 Group 2 + Halogens Flashcards
What is a common name given to group 2 metals?
Alkaline earth metals
What is the most reactive metal of group 2?
Barium
List three physical properties of group 2 metals
High melting and boiling points
Low density metals
Form colourless (white) compounds
The highest energy electrons of group 2 metals are in which sub shell
S sepubsgell
Does reactivity increase or decrease down group 2? Why?
Increase
Electrons are lost more easily because larger atomic radius and more shielding
What happens to the first ionisation energy as you go down group 2? Why?
Decreases
Number of filled electron shells increases so increase in shielding
Increased atomic radius so weaker force between outer electrons and nucleus
What type of reaction is between group 2 elements and oxygen?
Redox reaction
What are the products when group 2 elements reacts with water?
Hydroxide and hydrogen gas
Which group 2 element doesn’t react with water?
Beryllium
What are the products when group 2 elements react with a dilute acid?
Salt and hydrogen gas
What is formed when a group 2 oxide reacts with water?
Metal hydroxide
What group 2 metal oxide is insoluble in water?
Beryllium oxide
What is the trend in hydroxide solubility down group 2?
Increases down the group
What is Ca(OH)2 used for?
Used to neutralise soil
What is Mg(OH)2 used for?
Milk of magnesia- antacid to treat indigestion, heartburn, et cetera
What is calcium carbonate used for?
Present in limestone and marble used in building construction
What is the drawback of using calcium carbonate in construction?
Group 2 carbonate react with acid
What group elements are referred to as the halogens?
7
List two properties of halogens
Low melting and boiling points
Exist as diatomic molecules
What is the trend in boiling point down group 7? Why?
Increases down the group because
Size of atom increases as more occupied electron shells so stronger London forces of attraction between molecules which take more energy to break
What is the trend in reactivity during group? Why?
Reactivity decreases because
Atomic radius increases
Electron shielding increases
Ability to gain an electron and form 1- ions decreases
What is the trending oxidising ability down the group? Why?
Decreases down the group this is because CL has the fewest occupied electron shells, greater force of attraction between outer electrons and nucleus and thus is the easiest to gain electrons and be reduced
What is the trend in reducing ability of the halides down the group? Why?
Increases down the group this is because I minus has the most occupied electron shell so out of electrons are further from the nucleus, weakest force of attraction between outer electrons and positive charge of the nucleus and thus is the easiest to be oxidised and lose electrons
When a more reactive halogen displace is a less reactive halide what is the reaction called?
Displacement reaction
What is the colour of chlorine in water?
Pale green
What is the colour of bromine in water?
Orange
What is the colour of iodine in water?
Brown
What is the colour of chlorine in cyclohexane?
Pale green
What is the colour of bromine in cyclohexane?
Orange
What is the colour of iodine in cyclohexane?
Violet
Define disproportionation
The oxidation and reduction of the same element in a redox reaction
What type of reaction is the reaction of chlorine with water?
Disproportionation, chlorine is both oxidised and reduced
Why is chlorine added to drinking water?
It kills the bacteria in water and makes it safer to drink
What are two forms of the chlorate ion?
ClO- chlorate(I)
ClO3- chlorate(V)
What is the equation for forming bleach?
Cl2(aq) + 2NaOH(aq) -> NaCl (aq) + NaClO(aq) + H2O
NaClO is bleach
