chapter 9 - group 2, the alkaline earth metals Flashcards
What happens to the atomic radius down a group
The atomic radius down a group increases as there are more electrons
What happens to the ionisation energy down the group
The ionisation energy decreases down the group
What happens to the electronegativity down the group
The electronegativity down group to decreases
What happens to the melting point down group 2
It generally decreases however there is an outlier and this is magnesium (magnesium is melting point is very low in comparison to the downwards trend
What is meant by the term atomic radius
Atomic radius is the distance from the nucleus to the outermost electron
What is meant by the term first ionisation energy
This is the energy required to remove one mole of electrons from one mole of gaseous atoms
What is meant by the term electronegativity
Electronegativity is the tendency of an atom to attract a pair of electrons in a covalent bond
What is the term melting point mean
It is the average temperature at which a substance goes from solid to liquid
Why does the melting point generally decrease down the group 2
The positive ions get bigger so the attraction from the nucleus to the sea of electrons decreases as you go down group 2. Magnesium is an outlier and there has a much lower melting point than the general trend as it has a HCP
Our group 1 metals more or less reactive than group 2 metals
Group 1 metals are more reactive than group 2 metals as the outer electrons are harder to remove in group two and an outer electron is more easily lost in group 1 as it has one less proton.Therefore making group 1 metals more reactive than group 2
Reactions of group to metals
/ elements with water
Magnesium ribbon and water
Observation-no change/slight effervescence
Observation with a lit splint-no change
Observation with three drops of universal indicator- neutral/ yellow green
Reactions of group 2 metals/elements with water
Magnesium powder with water
Observation- slight effervescence
Observation with a lit splint-Squeaky pop/no change
Observation with three drops of universal indicator-green/blue PH8
Reactions of group 2 metals/elements with water
Calcium granules and water
Observation-effervescence, vigourous reaction, white precipitate
Observation with a lit splint-squeaky pop
Observation with three drops of universal indicator-blue PH 10
Reactions of group 2 metals/elements with water
Stronium(prediction)
Observation-catches flame
Observation with lit splint-squeaky pop
Observation with three drops of universal indicator-PH11/12
Reactions of group 2 metals/elements with water
beryllium (prediction)
Observation-effervescence
Observation with a lit splint-squeaky pop
Observation with three drops of indicator-pH 7/8
What is the equation one group to metals react with cold water to give a metal hydroxide and hydrogen
Ca + 2H2O = Ca(OH)2 + H2
What is the equation when magnesium reacts with steam to give a metal oxide and hydrogen
Mg(s) + H2O(g) = MgO(s) + H2(g)
What is the reaction when metal oxide reacts with water to produce metal hydroxide and no hydrogen gas
CaO(s) + H2O(l) = Ca(OH)2(aq)
What is the equation when group 2 metals react with an acid to produce an ionic salt and hydrogen gas
Ca(s) + H2SO4(aq) = CaSO4(aq) + H2(g)
What is the reaction when metal oxide reacts with an acid to produce an ionic salt and water
MgO(s) + 2HCl(aq) = MgCl2(aq) + H2O(l)
What happens to the solubility of the hydroxides as you go down the group 2
The solubility of the hydroxides increases as you go down the group
What happened to the solubility of sulphates as you go down group 2
The solubility of the sulphate decreases as you go down the group
What is a use of magnesium sulphate
Magnesium sulphate is used as an Epsom salt, it is used to treat low blood magnesium, it is a muscle relaxant and can help barium poisoning
What is magnesium hydroxide used for
Magnesium hydroxide is used to neutralise stomach acid for indigestion
What is calcium carbonate and CaO used for
They are used in flue gas desulfuristation and mainly in industry
What is calcium hydroxide used for
Calcium hydroxide is used mainly to neutralise acidic soil in agriculture and farming
What is CuSO4.2H2O used for
Plaster of Paris
What is Barium sulphate used for
Barium sulphate is used as a barium meal, useful when conducting x-rays on the GI tract/organs. It is insoluble so it won’t harm the patient
What are the properties of titanium
Titanium is a strong, light and resistant to corrosion
What is the first stage in turning titanium oxide into titanium
TiO2 + 2Cl2 + 2C = TiCl4 + 2CO
Titanium oxide is heated with carbon and chlorine gas to produce titanium chloride IV
What is the second stage in titanium extraction from titanium ore
TiCl4 + 2Mg = Ti + 2MgCl2
Carried out in inert Conditions and heated at a high temperature
it has to take place in inert conditions As magnesium is highly reactive, so magnesium won’t react with oxygen in the atmosphere
Why is titanium expensive to produce
Titanium is expensive to produce as it is conducted in inert conditions and this takes more money to maintain. The production of titanium involves batch reactions which take more money to produce in comparison to continuous reactions. Titanium is less abundant therefore it is also more expensive to get a hold of and produce.
