Periodic table origin and development

Johann Wolfgang Dobreiner

Johann Wolfgang Dobreiner

Discovered the Law of triads

Law of triads

Grouping of elements in three. The atomic mass of the middle element is the average of the other two.

23

Lithium has the atomic mass of 7, sodium has 23, and potassium has 39. If you add the 1st and 3rd one and divide it by 2, what is the mean of 1 and 3?

Alexander Beguyer De Chancourtois

The first person to organise elements by atomic weights.

The organizing of elements by atomic weights

Plotting a helical graph of the elements around a cylinder with a circumference of 16 units corresponding to the weight of oxygen.

John Newlands

devised the first periodic table and arranged the elements according to increasing weights

Explain the given law:Law of octaves by John Newlands

John Newlands arranged the elements according to increasing weights and observed that the properties of the elements are repeated after an interval of eight elements.

Dmitri Mendeleev and Lothar Meyer

__ created the first periodic table and was shortly followed by ?

Meyer and Mendelev arranged the elements by their mass. They proposed that __?

They proposed that certain properties periodically reoccur

Atomic Volume and(or) Molar Volume

Meyer formed his periodic law based on ____ or ____, which is the atomic mass divided by the density in solid form.

Henry Moseley

Rearranged the elements in the periodic table according to increasing atomic number.

How did Moseley rearranged the periodic table?

According to the increasing atomic number. This is the basis of the modern periodic table

Glenn Seaborg

discovered the transuranium element?

What is the transuranium element?

It has the atomic number of 92-102.

What else did Seaborg add?

The lanthanide and actinide

Periodic law

This law states that when elements are arranged in the order of increasing atomic number, elements with similar properties appear at periodic intervals.

The horizontal or row is called ___

Period or series of the elements in the periodic table

Group of family

Vertical column is the ____ of elements

Period Number

The ____ indicates the occupied highest main energy level of the elements.

Because of period number,

the elements belong to the same period or series

what are the lanthanide and actinide by glenn seaborg?

The Lanthanide and actinide series projected perpendicular to the plane of the periodic table

Elements with similar chemical properties have the same number of valence electrons. Because of this, the element belong to the same group family.

Chemical Families

Where are electrons found?

These are found in the outermost or highest main energy level.

Two ways of numbering the groups or families

1-18 groups and IA-VIIIA groups

1-18 groups

International union of pure & applied chemistry (IUPAC)

IA-VIIIA groups

older notation - US usage

Family 1- Alkali Metals

Single electron in their outermost energy level

soft, silver-white, shiny metals

it can be cut with a knife

good conductors of heat and electricity

can bond readily with other substances

they are very reactive

react violently with water

can easily burn and may explode

Lithium, Sodium, Potassium, Rubidium, Cesium, Francium

Family 1-Alkali Metals

Family 2- Alkali EARTH Metals

Never found in nature as uncombined elements

Have no valence electrons

Not as reactive as the other

Some are used and industries as alloys and some are important elements found in the human body

Family 3 up to 12 - Transition Metals

Have properties similar to one another and to other metals ut they are different from the properties of any other family

Also good conduct of heat and electricity

Brightly Colored and often used as color paint

Some are used for jewelry making, and component of some measurements tools

Can form many different compounds when losing one or more

Family 13 - Boron Family

Has 3 Valence electrons

Hard and brittle and never uncombined in nature

Visually combined with Oxygen

Often used for glass wares and cleaning compounds such as borox

Other metal elements are often used as components in the production of cars, trains, and planes

Boron

A metalloid (but in the boron family, the other is metal)

Carbon

A non mental and the element that is the basic of your life

Family 14- Carbon family

Two elements, silicon and germanium are metalloids, while ___ is non-metal

Almost all compounds that are important for our body have this

Metals under the carbon family are used for:

Metals are used for making cans that are tin and in production of paint and component in gasoline but removed because of its harmful effects.

Nitrogen

This makes up 75% of the atmosphere and is used for the production of pesticides, explosives, medicines, and dyes

Phosphorus

Belongs in family 15- Nitrogen family

an active non-metal used in making tips of matches and flares

Arsenic

Belongs in family 15- Nitrogen family

an ingredient in many insecticides

Antimony and Bismuth

Belongs in family 15- Nitrogen family

used in making alloys

Family 15- Nitrogen family

Has five valence electrons. The elements in this family: makes up 75% of the atmosphere, used for:

Pesticides

Explosives

Medicines

dyes

making tip of matches and flames

ingredient for insecticides

making alloys

Oxygen

The most abundant element in the Earth’s crust

Family 16- Oxygen family

Very important in all forms of life

Can form compounds with other elements or form a molecule by bonding itself such as ozone

Sulfur, selenium, and tellurium are brittle solids used in the manufacture of medicines, gunpowder, color grass red, and enamels, and alloys. What chemical family does this belong to?

Family 16- Oxygen family

Polonium

Part of family 16 - Oxygen Family which is an extremely rare element

Family 17

Have 7 valence electrons

Most active non metals

Never found in nature

Can share or gain 1 electron with other atoms to form compounds

Bond with other atoms to form salts, an important component in making toothpaste, used to melt snow and ice on streets, and used in photographic film

Bromine is one of the few liquid element while iodine and the other metalloid astatine are solids

Family 18 - Noble Gases

Normally unreactive

Do not readily form compounds with other elements

Also called as inert gases

Among noble gases, helium has 2 valence electrons while some have 8 electrons

Some of the noble gases are used as theatrical effects and colored signs, and neon lights

Radon is used to treat certain cancers

Argon and xenon are used in light bulbs and lamps

Lanthanoid Series

This is made up of soft, malleable metals that have high luster and conductivity. They are used in making various alloys and high-quality glass in industry.

Actinoid Series

Composed of elements which are radioactive. Uranium is used as fuel in nuclea powered electric generators

Basic Properties and trends on the periodic table

Atomic Size, Ionization Energy, Electron affinity, Electronegativty

Atomic Size

Defined by the atom’s atomic radius (One half the distance from the two nuclei of two adjacent atoms).

Ionization energy

Energy that is needed to remove the valence electron

Electron Affinity

Energy released or required when electrons are added to an atom in the gaseous phase

Electronegativity

The tendency of the atoms to attract electrons towards itself in the chemical bond

Linus Pauling

Developed the electronegativity values presented in the periodic table

Metalic Property

elements can be metal, non-metal, and metalloids

Octet Rule

It states that atoms tend to gain, lose, or share electrons until they are surrounded by eight valence electrons.

An atom either loses or gains electrons to achieve the electron configuration of the noble gases.

Octet Rule

Noble gases

These are stable and have high ionization energy. The s and p orbitals are completely filled.

Gilbert Lewis

Proposed the Lewis Electron Dot Structure

the Lewis Electron Dot Structure

It indicates the number of valence electrons in an atom represented by dots scattered on four sides of the atomic symbol