Group 2 And Group 7 Flashcards
What happens to Group 2 elements when they react?
They lose 2 electrons.
In group 2 what happened to the atomic radius down group 2?
Atomic radius increases down the group. This is because extra electron shells are added as you go down the group so the atomic radius gets larger.
In group to what happens the first ionisation energy down the group?
First ionisation energy decreases down the group.
Each element down group 2 has an extra electron shell compare to the one above these inner child shield the outer electrons from the attraction of the nucleus the extra shall also means the outer electrons are further away and so reduce its nucleus’s attraction. Both of these factors make it easier to remove the electrics resulting in a lower first ionisation energy.
What happens to reactivity down group 2?
Reactivity increases down the group.
As you go down the group, the first ionisation energy decreases. When group 2 elements they react they lose electrons, forming positive ions. The easier it is to lose electrons the more reactive the element, so reactivity increases down the group.
What happens to melting points down group 2?
The melting points generally decrease down the group.
Group 2 elements have a metallic structure with positive ions in a crystal structure surrounded by delocalised electrons. Going down the group the metal ions get bigger, but the number of delocalised electrons don’t change. There is a larger ionic radius, the further away the delocalised electrons are from the positive nuclei the message actually feel. So it takes less energy to break the bonds, which means melting points generally decrease as you go down the group. However there is a drop at magnesium because the of the crystal structure changes.
Group 2 elements react with water. What do they react to give?
One group 2 elements react, they are oxidised from a state of 0 to +2 forming 2+ ions. The group to metals react with water to give a metal hydroxide and hydrogen.
They react more readily down the group because the ionisation energy decreases.
In this reaction water is acting as the oxidising agent.
Solubility trends in group 2 depend on what?
Solubility trends tend to depend on the compound anion.
Compounds of group 2 elements that complain contain singly charged negative ions increase in solubility down the group.
Compounds of group 2 elements that contain doubly charged negative ions decrease in solubility down the group.
When reacting a group 2 elements with a hydroxide, how is solubility in group to?
The solubility decreases down the group.
Magnesium is the least soluble whereas barium is the most soluble.
When reacting a group 2 elements with a sulphate what happened to the reactivity in group 2?
Solubility increases up the group.
Magnesium is the most soluble whereas Barium is the least soluble.
Group 2 compounds are used to neutralise city, give some examples and how they work.
1) Calcium hydroxide is used in agriculture to neutralise acidic soils.
2) Magnesium hydroxide is used in some indigestion tablets as an antacid - this is a substance which neutralises excess stomach acid.
Ionic question for the neutralisation is
H^+ + OH- —> H2O
What is Barium Sulfate used in?
Barium sulphate is used in barium meals.
Barium Sulfate is opaque to x-rays, they won’t pass through it. It’s used in meals where the patient digests that the barium sulphate covers the tissues, making them show up on x-rays, showing the structure of the organs. It’s used to diagnose problems with the oesophagus, stomach or intestines.
Which group to element is used in the extraction of titanium?
Magnesium.
Magnesium is used as part of the process of extracting titanium from its ore.
The main titanium ore, titanium (IV) oxide is first converted to titanium (IV) chloride by heating with carbon in a stream of chlorine gas.
The titanium chloride is then purified by fractional distillation, before being reduced by magnesium in a furnace at almost 1000° C.
In this equation Mg is reducing agent:
TiCl4 + 2Mg —> Ti + 2MgCl2
What group 2 element is used to remove sulfur dioxide from fossil fuels?
Calcium oxide and calcium carbonate.
The acidic sofa dioxide can be removed from fluegases by reacting with an alkali-this process is called wet scrubbing.
Powdered calcium oxide/calcium carbonate can you be used both for this. A slurry is made by mixing calcium oxide/calcium carbonate with water. It’s then sprayed onto the flue gases. Sulfur dioxide reacts with the calcium oxide/carbonate and produces a solid waste product, calcium sulfite.
CaO + 2H2O + SO2 —> CaSO3 + 2H2O
CaCO3 + 2H2O + SO2 —> CaSO3 + 2H2O + CO
Halogens a highly reactive nonmetals of group 7.
Have a great state the boiling point trends in this group.
The boiling points increase down the group.
This is due to the increasing strength of the Van derWaals forces as the size and relative mass of the molecules increases. This trend is shown in the changes of physical state from fluorine (gas) iodine (solid).
Halogens a highly reactive nonmetals of group 7.
Have a great state the electronegativity trends in this group.
Electronegativity decreases down the group.
Electronegativity, is the tendency of an atom to attract the bonding pair of electrons. The halogens are all highly electronegative elements. But larger atoms attract less than smaller ones. This is because the electrons are further from the nucleus and I shielded by more electrons.
