3.1 Flashcards
periodicity
the trends that occur as you move across the periodic table
1st ionization energy
the energy needed to remove 1 mol of electrons from 1 mol of gaseous atoms
ionisation energy trend
decreases down a group and increases across a period
explanation of ionization energy trend
//electrons down a group have more shells+a larger radius-> electron shielding and distance=less attraction to nucleus// across a period more protons and electrons but no new shells so greater effective nuclear charge
trend of electronegativity
increases across a period and up a group
explanation of electronegativty trend
positive effctive attraction from nucleus is grater
atomic radius trend
decreases along a period
reason for atomic radius trend
more protons in nucleus, greater effective nuclear charge so the outer electrons are more attracted to the nucleus
electrons shielding
repulsion between electron shells
group 2 trends
down the group: reactivity increases, ionization energy decreases,atomic radius increases,melting point decreases
why does melting point decrease down group 2
the ions get bigger so the electrons holding it all together are further from the positive nucleus so they hold it together with less force
why does ionization energy decrease down group 2
outer shell electrons are further from the nucleus and increased electron shielding so its easier to remove them
Mg (s) + H20(l) ->
Mg(OH)2 (aq) + H2 (g)
Mg (s) + H20(g) ->
MgO (s) + H2 (g)
group 7 trends
down the group: atomic radius increases, melting point increases, electronegativity decreases, reactivity decreases down the group, ionization energy decreases down the group
explanation of group 7 meting points
induced dipole dipole interactions hold them together as the atoms get bigger there are more electrons so the induced dipole interactions are more powerful
reactivity of halogens
decreases down the group as it gets harder for them to gain an electron
precipitation reaction
a reaction in which two ionic solutions are mixed to give an insoluble compound
precipitate
insoluble salt
cations
positive
anions
negative
chlorine ion test
white AgCl precipitate forms when mixed with AgNO3, dissolves in dilute NH3
bromide ion test
cream AgBr precipitate forms when mixed with AgNO3, dissolves in concentrated NH3
iodide ion test
yellow AgI precipitate forms when mixed with AgNO3 does not solved
