Inorganic chemistry and periodic table Flashcards
How does atomic radius change across group 2?
increases due to more shells of electrons.
How does melting point change down group 2?
melting point decreases
due to metallic bonding becoming weaker
reducing the electrostatic attraction between cations and delocalised electrons
due to the metal ions and delocalised electrons having a greater distance from each other.
How does 1st ionisation energy change across group 2?
decreases
Because atomic radius increases due to more shells
increased shielding.
so more repulsive force of inner shells.
How does reactivity of group 2 change down the group?
increases down the group.
because more shielding
more repulsive force by inner electrons
so easier to form cation.
how do group 2 metals react with oxygen?
- will burn in oxygen, with Mg forming a bright white flame
what can be used to clean off the MgO before using in an experiment?
emery paper
give the balanced symbol equation for Mg and O
2Mg + O2 —-> 2MgO
How does Mg react with chlorine? give the equation
Mg + Cl2—-> MgCl2
How does Mg react with steam?
forms MgO + H2 by reacting with steam.
How does Mg react with warm water?
Forms Mg(OH) 2 + H2 through a much slower reaction
what pH would you expect a concentrated solution of Mg(OH)2 to be?
10-14
what would be OBSERVED when group 2 metals react with water? what is the case with calcium?
- fizzing
- metal dissolves
- the solution heats up
- calcium forms a white precipitate
How does the solubility of the hydroxides change down group 2?
- increases in solubility
what happens to group 2 solids that are not soluble?
they appear as white precipitates
how to group 2 ionic oxides react with water?
form hydroxides
why are ionic oxides basic?
oxide ions accept protons to become hydroxide ions.
order these from most to least soluble:
Mg(OH)2
Ca(OH)2
Ba(OH)2
Ba(OH)2
Ca(OH)2
Mg(OH)2
give a use of Mg(OH)2
used to neutralise excess acid in the stomach to treat constipation.
Give uses for Ca(OH)2
used to neutralise acidic soils in agriculture
rate from most to least alkaline:
Mg(OH)2
Ca(OH)2
Ba(OH)2
Ba(OH)2
Ca(OH)2
Mg(OH)2
How does the solubility of sulfates change in group 2?
- decreases