Module 3 Flashcards
Why are group 1 & 2 elements classified as s-block elements?
Their highest energy electron(s) are in an s-orbital or sub-shell.
Why can elements be classified as p-block elements?
Their highest energy electron(s) are in a p-orbital or sub-shell.
Why can elements be classified as a d-block element?
Their highest energy electron(s) are in a d-orbital or sub-shell.
What is meant by the term first ionisation energy?
The energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions.
What are the three factors that affect ionisation energy?
- atomic radius
- nuclear charge
- electron shielding
What is the general trend in ionisation energy across a period? Explain why.
- ionisation energy increases Due to: - atomic radii decrease - increase in nuclear charge - increase in nuclear attraction
What is the general trend in ionisation energy down a group? Explain why.
- ionisation energy decreases Due to: - increase in atomic radii - increase in electron shielding - decrease in nuclear attraction * increase in nuclear charge is outweighed!
Why is there a small decrease in ionisation energy between elements in group 2 to 3?
- group 3 elements have outer electron in a p-orbital, slightly further from the nucleus and easier to remove
Why is there a small decrease in ionisation energy between elements in group 5 to 6?
- group 6 elements start to have their electrons spin-pair, small repulsion between paired electrons and easier to remove
What is meant by the term metallic bonding?
Electrostatic force of attraction between positive metal ions and delocalised electrons.
What is the trend in reactivity down group 2? Explain why.
- reactivity increases
- atomic radius increases and electron shielding increases, electrons easier to remove
What is the trend in solubility down group 2? What is the effect on pH?
- solubility increases
- resulting solutions are more alkaline, higher pH
What is calcium hydroxide used for?
“Lime” to neutralise acidic soil
What is magnesium hydroxide used for?
Milk of magnesia to neutralise excess stomach acid
What is calcium carbonate used for?
Limestone as a building material
What is the limitation for the use of calcium carbonate in buildings and statues?
Reacts with acids in rainwater leading to erosion
What is the trend in boiling points down group 7? Explain why.
- increase
- London forces increase with increasing number of electrons
What is the trend in reactivity down group 7? Explain why.
- decreases
- increase in atomic radius
- increase in electron shielding
- ability to gain electron decreases due to increased repulsion
What is meant by the term disproportionation?
The oxidation and reduction of the same element in a redox reaction.
What colour is chlorine in both water and cyclohexane?
Pale green in both