Chapter 4 - Inorganic chemistry and the Periodic table (L) Flashcards
What is the definition of first ionisation energy?
The energy required to remove an electron from each atom in one mole of atoms in gaseous state
What is the definition of second ionisation energy?
The energy required to remove an electron from each 1+ ion in one mole of 1+ ions in gaseous state
What is the base cause of a high or low ionisation energy?
A high or low electrostatic attraction between the nucleus and outermost electron
What is electron shielding, and what is its effect on ionisation energy?
The idea that inner electrons shield the outer electrons from the electromagnetic pull of nucleus, weakening their attraction.
This hence decreases ionisation energy, as it is not as difficult to remove the outer electron
What are the 3 main factors to consider when explaining trends in ionisation energy?
- Nuclear charge
- Number of shells
- Electron shielding
What is the trend in reactivity down group 2?
Reactivity increases down the group, as less energy is required to remove the 2 outer electrons as you go down the group (first and second ionisation energy)
What is the trend in the vigorousness of reactions down group 2?
As you go down group 2, the reactions become more vigorous
What happens between group 2 elements and oxygen even without heating?
A slow reaction occurs, in which a surface coating of oxygen forms around the element, helping prevent further reaction
How is barium often stored and why?
Because it is the most reactive, it is often stored under oil to keep it reacting with oxygen and water vapour in the air
What is the general formula for group 2 reactions with oxygen? (M = group 2 element)
2M(s) + O2(g) -> 2MO(s)
What is the general formula for group 2 reactions with chlorine? (M = group 2 element)
M(s) + Cl2(g) -> MCl2
What is effervescence?
Bubbles in a liquid (fizz)
What is seen in the reactions with group 2 elements with water as you go down the group?
Increasing effervescence
What is the general formula for group 2 reactions with water? (M = group 2 element)?
M(s) + 2H2O(l) -> M(OH)2(aq) + H2(g)
What is the exception to the general formula for group 2 reactions with water?
Calcium, which forms a solid rather than aqueous hydroxide- Ca(OH)2 (s)
What is the formula for when Mg is heated in steam?
Mg(s) + H2O(g) -> MgO(s) + H2(g)
Why is hydrogen burned as it leaves the tube?
So it forms H2O, so there is not a highly flammable gas floating around in the lab
Why is it not a good idea to use water to put out a magnesium fire?
Because the magnesium will react with the water, feeding the fire more oxygen and releasing flammable hydrogen gas, which will further feed the fire
What type of oxides are group 2 oxides?
Basic oxides
What are basic oxides?
Oxides that can react with water to form alkalis
What is the general formula for group 2 oxides reacting with water?
MO(s) + H2O(l) -> M(OH)2 (aq)
What is the trend in solubility down group 2?
As you go down the group, solubility increases
What is the trend in the alkalinity of solution produced down group 2?
As you go down the group the pH (alkalinity) increases
What can be used to test for carbon dioxide?
Calcium hydroxide (limewater)- goes milky as a white precipitate forms. Calcium reacts with CO2 to form calcium carbonate (white precipitate)