Inorganic Chemistry- Periodicity Flashcards
What is a period?
A horizontal row of elements
What is a group?
A vertical row of elements
They have SIMILAR chemical properties because they have the same number of electrons in outer shell
Define periodicity
A repeating pattern of properties shown across different periods
Define the first ionisation energy
The amount of energy needed to remove one mole of electrons from one mole of atoms in the gaseous state
Trend of the first ionisation across a period
Where are the dips?
F.I.E increases
Similar shielding/shells
Increased proton number
Stronger electrostatic force between the nucleus and outer e- so more energy is needed to remove
Dips between Mg and Al/ P and S
Trend of atomic radius
Decreases
Similar shielding/shells
Increased proton number
Stronger electrostatic force between the nucleus and the outer e-
So electrons are held more tightly
Trend of positive ionic radius
Positive ion- smaller
More protons attracted to fewer electrons
Stronger nuclear attraction
They are held more tightly
Trend of negative ionic radius
Negative ion- bigger
Protons attracted to more electrons
Held less tightly
Define electronegativity
The power of an atom to attract the pair of electrons in a covalent bond
Trend of electronegativity
Increases
Similar shells/shielding
More protons
Pair of electrons in the covalent bond is more strongly attracted
Trend in melting point from Na to Al
Metallic bonding
Increases as more electrons and greater positive charge ion = stronger metallic bonds
Melting point of Si
Giant covalent molecule
Strong covalent bonds require a lot of energy to overcome
Trend in melting point from P to Cl
