periodic properties Flashcards
define periodic properties
properties which show a gradual change across a period which repeats from period to period. Repeating pattern is known as periodicity.
what are the S block elements
their outermost electrons are all in an S orbital (highest energy electron)
what do the trends in atomic radii depend on
the nuclear charge
the distance of the outer electrons from the nucleus
the shielding effect
how does atomic radius change across a period and why
decreases (nuclear charge increases)
how does atomic radius change down a group and why
increases (increased shielding)
why does gaining electrons cause an increase in atomic radii
increased electron-electron repulsion
what is the size of the first ionisation energy determined by (3)
the distance of outermost electron from nucleus
the number of protons
the shielding effect
what will increased proton number do to the IE
increase IE
how does increased shielding affect IE
decreases IE
how does larger ionic radius affect IE
decrease IE
why does magnesium have a higher melting point than sodium
Mg has one more proton than Na
Mg atom is smaller
Therefore has a stronger metallic bond and more energy is needed to break it.
what does the melting temperature of an element depend upon
strength of the bond and the structure
why does melting point rise from groups 1 to 2 to 3
the number of delocalised electrons increases.
why do the non metals in group 5, 6 and 7 have low melting points
they form simple molecules
held together by weak intermolecular forces
