3.1.1 Periodicity Flashcards
What are the rows in the periodic table called?
Periods
What are the columns in the periodic table called?
Groups
What blocks are there in the periodic table? (left to right)
S,P, D, F
What does a block mean in the periodic table? E.g. s-block
What sub shell the outer electron(s) are in
What is periodicity?
A repeating pattern across different periods
How was the historical periodic table arranged?
- Ordered in increasing mass
- Groups according to similar characteristics
- Left gaps for unknown elements and could predict properties
How is the current periodic table arranged?
- Ordered in increasing atomic number
- Groups = columns
- Periods = rows
What is ionisation energy?
The minimum amount of energy required to remove one mole of electrons from one mole of gaseous atoms
Is ionisation energy endothermic or exothermic?
Endothermic (+) requires energy
What is shielding?
Shells of electrons reduces the pull of the nucleus/ the positively charged nucleus being able to attract negatively charged particles
How does shielding affect ionisation energy? (increasing shielding causes …)
More electron shells -> more shielding effect -> weaker attraction between electrons in outer shell -> easier to remove electrons -> reduced ionisation energy
How does atomic radius affect ionisation energy? (increasing atomic radius causes …)
Greater atomic size -> further away the electrons are from the nucleus -> reduced electrostatic attraction between nucleus and outer electrons -> easier to remove electrons -> reduced ionisation energy
How does nuclear charge affect ionisation energy? (increasing nuclear charge causes …)
More protons in the nucleus -> greater nuclear charge -> greater electrostatic attraction between nucleus and electrons -> harder to remove electrons -> increased ionisation energy
What is the trend in ionisation energies down a group? Why?
Decreases:
- More electron shells -> increased atomic radius and shielding
What is the trend in ionisation energies across a period? Why?
Increases:
- More electrons and protons -> increased nuclear attraction
What are the exceptions in the trend in ionisation energies across period 3?
- Aluminium: electron in 3p shell, further away from nucleus and shielded by 3s so reduced ionisation energy
- Sulfur: no change in shielding but electron repulsion in one of the 3p orbitals so same ionisation energy as previous element
What is successive ionisation?
Removal of more than one electron from the same atom in a gaseous state
What is the trend in successive ionisation?
Increasing energy required
What drastically increases the successive ionisation energy?
Moving onto subshells/ shells that are closer to the nucleus
What’s the structure and properties of Graphite?
- Each carbon bonded 3 times with 4th electron delocalised & layers that slide over each other
- High melting point, conducts electricity, low density, insoluble
What’s the structure and properties of Diamond?
- Carbons bonded 4 times in tetrahedral shape (same to Silicon)
- High melting point, does not conduct electricity, insoluble
What’s the structure and properties of Graphene?
- One layer of graphite made up of hexagonal carbon rings & Delocalised, free moving electrons which strengthen the covalent bonds
- Conducts electricity, lightweight, transparent, very strong
What’s the structure of metallic bonding?
Metal cations donating outer electrons into sea of delocalised electrons in which they are electrostatically attracted to one another
What makes metallic bonding stronger?
- Greater cation charge
- More electrons in sea of electrons
- Smaller ionic radius
