Periodicity Flashcards
What is periodicity
Patterns that recur at regular intervals
Why do we group elements in the periodic table?
Because they have similar properties
In what order are the elements of the periodic table arranged?
Increasing atomic number
Which groups can be classed as s block?
Gp 1+2
Which group can be classed as d block?
Transition metals
Which groups can be classed as p block?
groups 3-7+0
Which group can be clased as f block?
lanthanides
How do you determine whether an element is in an s,p,d/f block?
Depending on which subshell electrons are being added to
Which energy level are the outer electronsin, in period 3 elements?
3rd
Why is sodium described as an s block element?
It is in the s block because the last orbitals to be filled are s orbitals.
In which block are the transition metals?
d block
Which groups are in the s block?
groups 1 and 2
Define first ionisation energy
The removal of 1 mol of electrons from 1 mol of gaseous atoms.
Write the equation to show the first ionisation of lithium
Li₍g₎ →Li⁺₍g₎ + e⁻
What is the general trend of ionisation energy across period 2?
It increases
Why does first ionisation energy generally increase across period 2?
Greater attraction between nucleus and outer electrons
Why are the first ionisation energies of period 3 lower than those of p2 ?
electrons further away and shielded
Why is there a drop in first ionisation energy between Be and B?
The electrons have started to fill p orbitals which are further away from the nucleus
Why is there a drop in first ionisation energy between Mg and Al?
The electrons have started to fill p orbitals which are further away from the nucleus
Why is there a drop in first ionisation energy between N and O?
electrons have started to pair in p orbitals. Electron is repulsed by the other electron making it easier to remove.
Why is there a drop in first ionisation energy between P and S?
electrons have started to pair in p orbitals. Electron is repulsed by the other electron making it easier to remove.
