By: Mrs. Rieseck-Terracio The Periodic Table By: Mrs. Rieseck-Terracio

What is the Periodic Table? Periodic Table: A chart that organizes all known elements by increasing atomic number, there is a periodic repetion of their chemical and physical properties. Helps organize your knowledge of Chemistry.

Modern Periodic Table

Development of the Periodic Table

Antoine Lavoisier Late 1790’s Compiled list of elements 23 elements Many known since ancient times Silver Gold Carbon Oxygen

In the mean time: 1800’s brought about an explosion of new elements. Invention of spectrometer used to identify new elements. Industrial revolution in mid 1800’s many new chemistry based industries: Petrochemicals Soaps and dyes Fertilizers

In the mean time: 1870 now are 70 elements known. Chemist overwhelmed with all the new information. Need a tool for organizing information. 1860 chemist agreed on a method of determining atomic masses of elements. With reproducibility came research between mass and elemental properties really began.

John Newlands English Chemist 1864 Proposed an organization of elements Arranged by atomic mass. Every 8th element had repeating properties.

John Newlands Law of octaves. Was not widely accepted. Did not work for all elements. Term “octave” to musical. In a couple of years was shown to be on the right path.

Meyer and Mendeleev 1869 German chemist Lothar Meyer. Russian chemist Dmitri Mendeleev Both demonstrated a connection between atomic mass and elemental properties. Mendeleev given more credit.

Dmitri Mendeleev Atomic mass Columns of similar properties. 1st periodic table. Left blank spaces Said they were for undiscovered elements.

Dmitri Mendeleev Not completely correct. Some newly discovered elements didn’t “fit”.

Mendeleev’s Table

Henry Moseley 1913 English chemist Discovered the Atomic Number.

Henry Moseley 1913 English chemist Discovered the Atomic Number. Rearranged the periodic table according to Atomic Number. Problems were solved.

Periodic Law Periodic Law: States that when the elements are arranged by increasing atomic number’ there is a periodic repetition of their chemical and physical properties.

Modern Periodic Table Arranged by increasing atomic number. Consists of boxes, usually containing: Element symbol Atomic number Atomic mass

Just a Sample

Modern Periodic Table Boxes arranged in Groups 1A-8A are known as Representative Elements 1B-8B are known as Transition Elements Boxes also arranged in Periods 7 periods

Representative Elements Representative Elements: Groups of elements in the modern periodic table that are designated with an A (1A through 8A) and possesses a wide range of chemical and physical properties.

Transition Elements Transition Elements: Groups of elements in the modern periodic table that are designated with a B (1B through 8B) and are further divided into transition metals and inner transition metals.

A way of organizing & classifying elements Arranged in rows and columns

Columns The vertical (up and down) columns of the periodic table (there are 18) are called groups or families. Elements in the same group or family have similar characteristics or properties.

Rows The horizontal rows of the periodic table are called periods. Elements in a period are not alike in properties. The first element in a period is usually an active solid, and the last element in a period is always an inactive gas.

Rows Atomic size (number of protons) decreases from left to right across a period. Atomic mass (number of protons) increases from left to right across a period.

Rows Metals are on the left Non-metals are on the right

ALKALI METALS very reactive metals that do not occur freely in nature malleable, ductile, good conductors of heat and electricity. softer than most other metals can explode if they are exposed to water

not found free in nature ALKLINE EARTH METALS metals very reactive not found free in nature

TRANSITION METALS ductile and malleable, and conduct electricity and heat iron, cobalt, and nickel, are the only elements known to produce a magnetic field.

RARE EARTH ELEMENTS many are man-made

are ductile and malleable OTHER METALS are ductile and malleable are solid, have a relatively high density, and are opaque

METALLOIDS have properties of both metals and non-metals some of the metalloids, such as silicon and germanium, are semi-conductors. This means that they can carry an electrical charge under special conditions. This property makes metalloids useful in computers and calculators

NON-METALS not able to conduct electricity or heat very well very brittle, and cannot be rolled into wires or pounded into sheets exist in two of the three states of matter at room temperature: gases (such as oxygen) and solids (such as carbon). have no metallic luster, and do not reflect light.

HALOGENS "halogen" means "salt-former" and compounds containing halogens are called "salts" exist in all three states of matter: Solid- Iodine, Astatine Liquid- Bromine Gas- Fluorine, Chlorine

NOBLE GASES do not form compounds easily