Chemistry: Periodic table

Doberenier Law of triads

A principle stating that elements can be grouped in sets of three, or triads, where the atomic weight of the middle element is approximately the average of the other two elements in the group.

Examples of dobereniear triads

Li, Na, K

Ca, Sr, Ba

Cl, Br, I

S, Se, Te

AEB de chancourtois

cylindrical periodic table

Newlands Law of Octaves

A principle stating that when elements are arranged by increasing atomic weight, every eighth element exhibits similar properties, analogous to musical octaves.

Physical properties used by Lothar Meyer (vs atomic weight)

include atomic volume, melting point, boiling point

Eka Aluminum

gallium

Eka silicon

germanium

eka boron

scandium

old Mendeleev periodic law

the properties of elements are the periodic functions of their atomic weights

new Mendeleev periodic law

the properties of elements are the periodic functions of their atomic number

Henry Moseley

a plot of root(freq) against atomic number, which gave a more straight line ,thus proving that atomic number is a more fundamental property of an element rather than its weight

total number of naturally occurring elements

94

Discovery of plutonium (atm no = 94)

Glenn T Seaborg, who also discovered seaborgium (at. no. 106)

magic numbers of periodic table

2, 8, 8, 18, 18, 32, etc

Rutherfordium in Russian

kurchatovium

general electronic config of s block

ns(1-2)

general electronic config of p block

ns(2)np(1-6)

general electronic config of d block

ns(0-2)[n-1]d(1-10)

general electronic config of f block

ns(2)[n-1]d(0-1)[n-2]f(1-14)

metals constitute how much percent of the periodic table

80%

Atomic radii can be measured by

X-ray diffraction and spectroscopic methods

Ioninzation enthalpy order of period 2

Li<B<Be<C<O<N<F<Ne

electron gain enthalpy order

S>Se>Te>Po>O

Cl>F>Br>I>At

Electon affinity order of period 2

Ne<Be<N<B<Li<C<O<F

EN of F

4.0

Basic Oxides

Na2O

Acidic Oxides

Cl2O7

Amphoteric oxides

Al3O3, V2O5, Cr2O3, As2O3

In the periodic table Atomic Volume Trend Is:

It first decreases then increases

Electron Affinity Of halogens

Cl>F>Br>I

Bond energy of halogens

Cl2>Br2>F2>I2