3.1.1 Periodicity Flashcards
what order is the periodic table arranged in
increasing atomic number
what are the vertical columns called
groups (1 to 18)
what are the horizontal rows called
periods
what are the blocks
correspond to electron found on highest subshell
what is periodicity
there are repeating trend in properties across each period
what is ionisation energy
how easily an atom loses electrons and forms positive ions
what is first ionisation energy
the energy needed to remove one electron from each atom in a mole of gaseous atoms of an element to form one mole of gaseous 1+ ions
what are the ionisation energy equations
Na(g) ==> Na(g)1+ + e-
Na(g)1+ ==> Na(g)2+ e-
which 3 factors effect the first ionisation energy of an element
1) atomic radius
2) nuclear charge
3) electron shielding
what is atomic radius and how does it effect ionisation energy
-greater the distance between outer electrons
-less nuclear attraction
-electrons easily lost
-LOWEST AT TOP RIGHT OF PERIODIC TABLE:
- across period: more protons, means more positive charge of nucleus, means electrons are pulled closer together, reducing atomic radius
explain nuclear charge
-more protons in nucleus
- greater nuclear attraction
explain electron shielding
- inner shell electrons repel outer electrons (all negative)
- causes repulsion called shielding effect
- reduces nuclear attraction
what is nuclear attraction
attraction between positive nucleus and outer electrons
how many IE’s will an atom have
- as many electrons as it has
why does IE increase with successive energies
- less electrons, e- pull closer to nucleus and is nearer it, more IE
- as size of ion is smaller
what is the definition of 2nd ionisation energy
the amount of energy needed to remove one electron from from each 1+ ion in one mole of gaseous ions of an element and form one mole of 2+ gaseous ions