Group 2 And Group 7 Elements
No description yet. This curated deck is ready for daily study.
Card preview (24)
What do group 2 elements do to react?
Lose their outer two electrons to form 2+ ions. Their ions then have the structure of a noble gas
What happens as you go down the group to the atomic radius?
The atomic radius gets larger. This is because extra electron shells are added as you go down the group
What happens to first ionisation energy as you go down group 2?
It decreases
Why does the first ionisation energy as you go down the group decrease?
Each element down group 2 has an extra electron shell compared to the one above The extra shell means that outer electrons further away from the nucleus which greatly reduces the nuclear’s attraction Making it easier to remove electrons
What happens to the positive charge of the nucleus as you go down group 2 metals and why doesn’t this matter?
It does increase as you down the group due to extra protons but this effect is overridden by the effect of the extra shells
What happens as you go down the group to the first ionisation energy?
The first ionisation energy decreases due to increasing atomic radius and shielding effect
What happens as you down the group 2 metals to the reactivity?
When group 2 elements lose electrons forming positive ions the easier it is to lose electrons the more reactive the element so reactivity increases down the group
What structure do group 2 metals tend to have?
Typical metallic structures with positive ions in a crystal structure surrounded by delocalised electrons from the outer electron shells
What happens as you go down group 2 that’s related to melting point?
The metal ions get bigger but the number of delocalised electrons stay the same and the charge on the ion also stays the same
The larger the ionic radius?
The further away delocalised electrons are from the positive nuclei and the less attraction they feel. So takes less energy to break the bonds meaning the melting point generally decrease as you down the group.
What’s the exception to this trend?
Blip at magnesium because crystal structure changes
What happens when group 2 elements are react with water?
They are oxidised from a state of 0 to +2 forming M2+ ions M=>M2+ +2e- Water is the oxidising agent
What happens to solubility down the group 2 elements?
Generally, the compounds of group 2 elements contain singly charged negative ions increase in solubility down the group whereas compounds contain doubly charged negative ions decrease down the group
Solubility of group 2 elements hydroxides?
Top element-magnesium- least soluble Barium- most soluble
Group 2 metal solubility sulfate?
Magnesium is the most soluble Barium is the least soluble
Details on the least soluble compounds of group 2 metals?
MgOH2 has very low solubility sparingly soluble Most sulfates are soluble in water, barium sulfates is insoluble
How do you test for sulfate ions?
For acidified barium chloride is added to solution containing sulfate than a white precipitate of barium sulfate is formed. You need to acidity solution with HCl to get rid of any lurking sulfites or carbonates which also produce a white precipitate
What are group 2 metals known as?
Alkaline earth metals Many common compounds used to neutralise acids
What is calcium hydroxide used for?
Slake lime Ca(OH)2 is used in agriculture to neutralise acid soils
Magnesium hydroxide used for?
Used in some indigestion tablets as an antacid- substance which neutralises excess stomach acid
How do both of these work?
Ionic equation for neutralisation H+ (aq)+ OH-(aq) => H2O (l)
What’s barium sulfate used for?
Barium meal
What are x-ray’s traditionally good for?
Finding broken bones but pass through soft tissue so soft tissue doesn’t show up like the digestive system don’t show up on conventional X- Ray pictures
How does barium sulfate work?
Opaque to X-Rays so doesn’t pass through it Used in barium meals to help diagnose problems with oesophagus, stomach or intestines Patient swallows barium meal which is a suspension of barium sulfate. Barium sulfate coats tissue making them show up on X-rays showing structure of the organs