Unit 1 - Periodicity Flashcards
In a period of the table, what do all of the elements have?
The same number of electron shells.
What do the number of increase by one going across a period?
The number of electrons and protons.
The number of electrons and protons.
The general trend across period 2 is a decrease in atomic radii.
What affect does having an extra shell have on the atom?
This has the affect of reducing the attraction of the positive nucleus to the outer electrons as MORE ELECTRON SHELLS are added each time. Known as the “Shielding Effect”.
As the attraction is reduced as each new shell is added, how does this effect atomic radii?
The atomic radii increases down groups.
What is the 1st ionisation energy?
The 1st ionisation energy is the energy per mole required to remove one electron from the outer shell of an atom in the gaseous state.
What is the 2nd ionisation energy?
The 2nd ionisation energy is the energy per mole required to remove the second electron from the same atom as the 1st ionisation energy in he gaseous state.
How does atomic size change as you go down a group?
It increases
How does electronegativity change as you go across a group?
It increases - more protons means greater attraction between them and the outer electrons which are more tightly held on to
How does the first ionisation energy change across a period?
It increases - more protons means greater attraction between them and the outer electrons which are more tightly held on to
How does electronegativity change as you go down a group?
It decreases - more electron shells are added which “shields” the positive protons and the outer electrons meaning they’re not held as tightly and are further away
How does the first ionisation energy change as you go down a group?
It decreases - more electron shells are added which “shields” the positive protons and the outer electrons meaning they’re not held as tightly and are further away
Which is easier:
Removing an electrons from a half filled shell
Removing an electron from a full shell
Half filled shell - removing electrons from full shells is very hard to do and requires a lot of energy
What is the reaction of the first ionisation energy of sodium?
Na(g) = Na+(g) + e-
