periodic table. what does periodic mean? definition- name some things that are periodic

Periodic Table

What does periodic mean?

Definition-

• Name some things that are periodic.

History

Mendeleev (1887)-

• At that time 63 elements were known

• He tried to arrange them according to a variety of properties.

• Arranged them according to atomic mass and found it worked quite well, with only a few gaps.

• Developed first periodic table.

Mendeleev’s Periodic Table

Moseley (early1900’s)-

• Information about the number of protons allowed him to arrange elements by atomic number.

• No gaps when arranged by atomic number.

Glenn Seaborg-(1940-1950’s)

• Actinide series introduced, taken from the transition metals.

Periodic Law

Physical and chemical properties of the elements are periodic functions of their atomic numbers.

There are three (3) major sections to the periodic table.

• Find the jagged (stepped) line to the right-hand side of the table!

Using the next slide and your blank Periodic Table…

• Color in the different areas of your Periodic Table-

Metals, Non-Metals and Metalloids.

Metals

• these are the elements found to the left of this line.• Characteristics:

good conductors of heat and electricity

shiny (metallic luster)

high melting temperatures

ductile-drawn into thin wires

malleable-molded, flattened into thin sheets.

Nonmetals

• these are the elements found to the right of the jagged line.

• Characteristics:

poor conductors of heat and electricity

dull (earthy luster)

low melting temperatures

brittle-nonmetals that are solid

Metalloids

• found immediately to either side of the line.Exception Aluminum (Al)

• Characteristics: They are mutantsThey have properties of both metals and

nonmetals.May have shiny or dull lusterConduct heat and electricity better than

nonmetals, but not as good as metals.

B-Si-Ge-As-Sb-Te-Po-At

Groups/Families

• are vertical columns.

• Elements in a group/family have similar but not identical properties.

Periods

• Horizontal rows on the periodic table.

• Properties of elements in a period change greatly from left to right.

• Left-solid and reactive----Right–gas and inactive

Group 1 ALKALI METALS

• very reactive

• they are soft metals (can be cut with a knife)

• Melt at low temperatures for metals

• have low densities

• hydrogen is NOT part of this group

Group 2ALKALINE EARTH METALS

• reactive, but less than Group 1

Groups 3-12TRANSITION METALS

• less reactive than group 1 or 2

• found in ores (hematite, magnetites...)

• same properties of metals

RARE EARTH ELEMENTS-

• Lanthanide series- have steel-like properties.

found in small quantities

• Actinide series-

most are man-made

most are radioactive

Group 13 Boron Group

• contains metals and metalloids

Group 14 Carbon Group

• contains metals, metalloids and nonmetals

Group15 Nitrogen Group

• contains metals, metalloids and nonmetals

Group 16 Oxygen Group-• contains metalloids and nonmetals

Group 17 Halogens-

• called the HALOGENS(meaning salt -makers)

• contains metalloids and nonmetals

Group 18 Noble Gases

• do not form ions

• they are very nonreactive

• all exist in the earth’s atmosphere