3. Periodicity Flashcards
Effective nuclear charge
outer electrons increase with the group number of the element and across a period
First Ionization energy
The energy required to remove one mole of electrons from 1 mole of gaseous atoms in their GROUND STATE
Electron affinity
energy change that occurs when one mole of electrons is added to one mole of gaseous atom
Electronegativity
Ability of an atom to attract electrons in a covalent bond
coordinate bond
uses a lone pairof electron to form a covalent bond
Ligand
is a species that uses a lone pair of electrons to form a coordinate bond with a metal ion.
A chelate
is a complex containing at least 1 polydentate ligand.
Nuclear charge trend
Increases down the group, Increases across a period
Atomic radius trend
Increases- group;;
Decreases- period
Ionic radius trend
Increases- group;;
Decreases- period
Electron affinity trends
decreases- group;;
increases- period
Ionization energy trends
decreases- group;;
increases- period
most electronegative element
Fluorine
M.P trends for group 1
decreases down the group
M.P trends for group 7
increase down the group
group 18 ft
colourless gasses, monoatomic, unreactive, stable octet
Group 1 physical properties
good conductor, low density, shiny
grp1 chem properties
very reactive, form ionic compounds with non-metals
group1 reaction w water (hydrogen + metal hydroxide)
2K + 2H2O ->2KOH + H2
=Lithium- floats, reacts slowly, releases hydrogen but maintains its shape.
=Sodium- reacts vigorously, releases hydrogen, heat produced to melt unreacted metal.
=K- more vigorous, ignites hydrogen produced
<2k+2H2O=2K++2OH-+H2>
grp 17 phy properties
coloured, gases - solids
Grp 17 chem properties
very reactive (reactivity decreases down the group), form ionic compound w metals and covalent w non metals
how does displacement reaction under grp 17 elements occur?
The more reactive halogen displaces the ions of the less reactive halogen from its compounds
2KBr +Cl2 = 2KCl+Br2
Reaction w grp1 metals
halogens react w group 1 metals to form ionic halides
2Na + Cl2 = 2NaCl
