Group 2 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 3 physical properties of group 2 metals?
- High melting and boiling point
- Low density metals
- Form white compounds
Does reactivity increase or decrease down group 2? Why?
It increases. Electrons are lost more easily because of the larger atomic radius and more shielding which decreases the pull on electrons.
What happens to the first ionisation energy as you go down group 2? Why?
It decreases because the number of filled electrons increase down the group which means an increased shielding. Increased atomic radius means weaker attraction.
What type of reaction is the reaction between group 2 elements and oxygen?
Redox reaction
What are the products when group 2 elements react with water?
Hydroxide and hydrogen gas
Which group 2 elements doesn’t react with water?
Beryllium
What group 2 element reacts very slowly with water?
Magnesium
What is oxidised and what is reduced in a reaction between group 2 metal and water?
The metal is oxidised and one hydrogen atom from each water is reduced
Write and equation for the reaction of barium and water.
Ba + H2O -> Ba(OH)2 + H2
What are the products when a group 2 element reacts with a dilute acid?
Salt and hydrogen gas
What is formed when group 2 oxides react with water?
Metal hydroxide
Write an equation for the reaction of calcium and oxygen
2Ca + O2 -> 2CaO + H2
Write an equation for the reaction of calcium and hydrochloric acid
Ca + 2HCL -> CaCl2 + H2
Write an equation for the reaction between a group 2 oxide and water.
MgO + H2O -> Mg(OH)2
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 as solutions contains more OH- ions. Mg(OH)2 is slightly soluble and Ba(OH)2 creates a strong alkaline solution and is much more soluble in water
What is Ca(OH)2 used for? Write an equation related to one of its uses.
Calcium hydroxide is used to neutralise acids in the soil, forming neutral water.
Ca(OH)2 + 2HCl -> H2O + CaCl2
What is Mg(OH)2 used for?
Acts as an antacid for treating acid indigestion, ‘milk of magnesia’.
What is calcium carbonate used for?
Present in limestone and marble and used in building construction
In reactions what do group 2 elements act as?
Reducing agents
Explain why group 2 elements are reducing agents?
They reduce another species
State and explain the trend in alkalinity of the solution formed when group 2 oxides are added to water?
Down group 2, the solubility of the metal hydroxide increases, increasing the pH and alkalinity
Explain why ZnCl2 is a salt
H+ replaced by Zn2+
Predict the formula of the zinc salt that could be formed by adding an excess of zinc to phosphoric acid?
Zn3(PO4)2
Describe and explain the trend in reactivity of the Group 2 elements with dilute HCl as the group is descended
- Reactivity increases down the group
- Atomic radius increases down the group
- Shielding increases which is outweighed by increased proton charge
- Nuclear attraction decreases/ionisation energy decreases
Suggest why ice has a higher melting point than solid ammonia
- Ice has stronger hydrogen bonds
- O has 2 lone pairs and N has 1
- O is more electronegative
State one benefit for public health, of the reaction between chlorine gas and water
Removes germs/disinfects
What trend in the behaviour of group 2 carbonates would be observed by the student?
- Ease of thermal decomposition decreases down the group
