Periodicity Flashcards
what is ionisation energy
a measure of how easily an atom loses an electron to form a positive ion
what do successive ionisation energies allow us to predict
- the number of electrons in the outer shell
- the group of the element in the periodic table
- the identity of an element
what is the defenition for ionisation energy
the first ionisation energy of an element is the energy required to remove one electron from each atom in one mol of gaseous atoms to form one mol of gaseous 1+ ions
what factors affect ionisation energy
- if atomic radius increases, ionisation energy will decrease because the outer electrons are further from the nucleus , experience less attraction and so less energy required to remove them
-if the size of the nuclear charge increases , ionisation energy increases as the outer electrons will experience increased nuclear attraction and require more energy to remove them
-if the number of shells of electrons increases , ionisation energy will decrease because the inner electrons are repelling the outer ones (sheilding)
what are the first ionisation energy trends down groups and across periods
decrease in the first ionisation energy down every group . increase in the first ionisation energy across each period . but falls in two places
why do first ionisation energies decrease down a group
atomic radius increases , so distance increases , resulting in less nuclear attraction . more inner shells , so the sheilding effect on outer electrons increases resulting in a decreased force of attraction
why is each successive ionisation energy larger than before
as each electron is removed there is less repulsion between electrons and each shell will be drawn slightly closer to the nucleus. as the distance decreases slightly the nuclear attraction increases and more energy needed
what is the defenition for successive ionisation energies
successive ionisation energies are a measure of the energy required to remove each electron in turn .
why is there a large increase in successive ionisation energies
evidence for shells . large increases in ionisation energies are because an electron has been removed from a different shell , closer to the nucleus and with less sheilding from inner electrons
what is the defenition for periodicity
periodicity is a repeating trend in properties of the elements across each period of the periodic table
Where is there anomalies in group 3 of the ionisation energies and why
Mg and aluminium , mg is above as the electron configuration even though aluminium has a higher nuclear charge
Alumiums outer electron is further away and more shielded than mangnesium as it’s in p not s
Sulfur is lower than phosphorus as sulfurs electron confiuration as the extra paired electrons repell and this requires less energy
Where do the giant metallic structures go up to in period 2
Li to c
What are the simple molecules in period 2
N,O,F,Ne
What are the giant structures in period 3
Na to s
