Periodicity Flashcards
What groups are in S block on the periodic table?
1 and 2
What groups are in P block on the periodic table?
3 4 5 6 7 0
What groups are in D block on the periodic table?
Transition metals
Trend in atomic radius along period 3?
Decreases
Each subsequent element gains a proton meaning the nucleus gains a charge.
Stronger attraction between nucleus and electrons causing the atomic radius to decrease.
Electrons are added to the same electron shell meaning there is limited change in shielding
Trend in melting point across period 3?
From sodium to aluminium the MP increases.
They all have a metallic structure and the metallic bonds get stronger as the metal ions have an increasing positive charge (extra protons). There is also an increasing number of delocalised electrons and the size of the metal ion decreases.
Large increase to silicon.
Giant covalent structure - many strong covalent bonds in a tetrahedral structure.
Sharp decrease to phosphorus, sulfur and chlorine.
Simple molecular structures with weak IMFs.
Phosphorus exists as P4, sulfur exists as S8 and Chlorine exists as Cl2.
Therefore Sulfur has the highest MP as it has the largest molecules - stronger VDW forces.
Argon has the lowest MP as its monatomic so it has the weakest VDW forces.
Trend in first ionisation energies across group 3?
General increase
- Increase in nuclear charge across the period
- Shielding remains consistent as electrons are removed from the same shell
- Smaller atomic radius as the outermost electron is held to the nucleus by a greater charge
There is a decrease from Mg to Al:
Al outer electron in 3p subshell has a higher energy - easier to remove electron compared to 3s.
There is a decrease from P to S:
In P there are no paired electrons in the 3P shell.
In S there is a paired electron pair in 3P. These two electrons repel meaning less energy is required to remove the paired electron.
