chem f4c4

Antoine Lavoisier

Classified elements into 4 grps

(gases, non-metals, metals, oxides)

J.W. Dobereiner

grouped elements into triad groups (3 elements w similar chem props)

John Newlands (1N)

arranged elements according to increasing atomic mass + law of octaves

Lothar Meyer (3M)

plotted graph of atomic volume against atomic mass

Dmitri Mendeleev (3M)

arranged elements according to increasing atomic mass + arranged elements w similar chem props in the same vertical columns

Henry Moseley (3M)

arranged elements according to increasing proton number

Periodic table of elements

elements ARE arranged according to increasing proton number

Group

Vertical columns in the Periodic Table of Elements

Period

horizontal rows in the Periodic Table of Elements

for grp, if they have 1-2 valence elec

grp 1 or 2

for grp, if they have 3-8 valence elec

grp 13 to 18 (+10 la)

for period, how to determine?

number of shells occupied, so 3 shells like for 2.8.5 is in period 3

grp 1 - 13

metals

grp 14 - 18

non-metals

grp 1

alkali metals

grp 2

alkali earth metals

grp 17

Halogens

grp 18

noble gases

grp 3 - 12

transition elements

grp 18 elements phy props?

low mp/bp, colourless gas, cannot conduct electricity, low density

why the mpbp increase going down grp 18?

coz going down grp 18, the atomic size increases + attraction forces btw atoms bcms stronger + more heat energy is needed to overcome the strong forces

attraction force btw atoms =

Van der Waals attraction forces