Topic 4: Inorganic Chemistry Flashcards
From Original Flashcards - Not Updated
How do you measure atomic radius?
Half the distance between the two nuclei of the two identical atoms that are bonded together.
How does the atomic radius change across the period?
Decreases
Why does atomic radius decrease across the period?
More protons so an increased positive nuclear charge. So an increased attraction between the nucleus and the electrons. Drawing the electrons closer so a smaller atomic radius
What happens to atomic radius down the group?
Increases
Why does atomic radius increase down the group?
Number of electron shells increases, so that outer electron is further from the nucleus. Increased shielding from shells leads to decreased attraction to the nucleus and an increased atomic radius
What happens to the value of the first ionisation energy across the period?
Increases
Why does first ionisation energy increase across the period?
More protons means more attraction between the nucleus and electrons. So smaller ionic radius and greater attraction.
What happens to ionisation energy as you enter a new sub shell and why?
Drops as the new sub shell is of higher energy level so more energy is needed to remove.
on second filling the electrons are in opposite directions in same filling so repel one another
What happens to the ionisation energy value as you go down the group?
Decreases
Why does the Ionisation energy decrease down the group?
Atomic radius increases so electrons are further away from the nucleus and more shielding so attraction is less as you descend the group
What happens to the value of successive ionisation energies?
It increases
Why do successive ionisation energies increase?
when an electron is removed the other ones are pulled closer to the nucleus so more energy is needed to separate the electrons due to increased attraction.
What happens to successive ionisation energy as you drop an electron shell?
there is more attraction as you are closer to the nucleus so the ionisation energy increases
how do group 2 oxides react with acids?
Forms a salt and water
MgO + 2HNO3 -> Mg(NO3)2 + H2O
How do group 2 hydroxides react with acids?
forms the salt and water
Ca(OH)2 + H2SO4 -> CaSO4 + 2H2O
How does magnesium react with water?
Reacts with water as steam.
Forms magnesium oxide and hydrogen.
Mg + H2O -> MgO + H2
How do group 2 elements react with water?
Produces the metal hydroxide and hydrogen. Group 2 hydroxides can be soluble.
Sr + 2H2O -> Sr(OH) + H2
How does a group 2 element react with chlorine?
Forms the metal chloride.
Ca +Cl2 -> CaCl2
What is the general formula for metal chlorides?
XCl2
with x being the metal
How does a group 2 element react with oxygen?
Forms the metal oxides.
2Mg + O2 -> 2MgO
What colour do group 2 oxides burn?
Typically white.
Magnesium oxide is definitely white.
What happens to ionisation energy as you go down group 2? Why?
Ionisation energy decreases as the electron is further away from the nucleus and more shielding means less attraction.
What happens to reactivity as you go down group 2? Why?
Increases as it is easier to loose the two electrons due to the reduced ionisation energy
Are group 2 elements oxidising or reducing agents?
Reducing Agents.
They are oxidised themselves as they loose 2 electrons.
How do group 2 elements react with acids?
Produces metal salt and hydrogen gas.
Mg +H2SO4 -> MgSO4 + H2
What happens when an oxide reacts with water?
Produces a hydroxide, which dissolves in water.
CaO + H2O -> Ca(OH)2 + H2
What is the trend in solubility of group 2 hydroxides?
Increasingly soluble down the group.
Mg(OH)2 - Milk of magnesia, not very soluble.
Ca(OH)2 - Lime Water, very soluble
What effect do hydroxides have on the solution?
Makes the solution Alkali. The higher the hydroxide ion concentration the more alkaline it is.
what effect does solubility have on alkalinity?
Lower solubility means that there is a low concentration of hydroxide ions so is less alkaline.
What is the trend in solubility of group 2 sulphates?
Less soluble down the group.
MgSO4 - Highly soluble in water.
BaSO4 - Insoluble in water - forms a white precipitate
Are group 2 carbonates soluble in water?
No - Insoluble
Are group 2 nitrates soluble in water?
Yes - Soluble
What happens to the thermal stability of group 2 carbonates and nitrates as you go down the group?
Become more thermally stable.