the periodic table review concepts demetri mendeleev by 1860 about 60 elements were known and a...
TRANSCRIPT
The Periodic TableREVIEW CONCEPTS
Demetri Mendeleev By 1860 about 60 elements were known and a method was needed for organization.
In 1869, Russian chemist Dimitri Mendeleev proposed arranging elements by atomic weights and properties.
The table contained gaps but Mendeleev predicted the discovery of new elements.
Important Features Atomic Number Symbol Name Atomic Mass
We’ll learn more about these later…
What is the ATOMIC NUMBER?
oThe number of protons found in the nucleus of an atom
Or
oThe number of electrons surrounding the nucleus of an atom.
What is the SYMBOL?
oAn abbreviation of the element name.
What is the ATOMIC WEIGHT?
oThe number of protons and neutrons in the nucleus of an atom.
How do I find the number of protons, electrons, and neutrons in an element using the periodic table?
o # of PROTONS = ATOMIC NUMBER
o # of ELECTRONS = ATOMIC NUMBER
o # of NEUTRONS = ATOMIC _ ATOMIC
WEIGHT NUMBER
Elements share traits by FAMILIES (GROUPS) and PERIODS
PERIODS
FAMILIES (Group)
The Elements are Separated into 9 Different Families on the Periodic Table
1. Alkali Metals
2. Alkaline Earth Metals
3. Transition Metals
4. Rare Earth Metals
5. Halogens
6. Noble Gases
7. Metalloids
8. Non-Metals
9. Other Metals
FAMILIES : Alkali Metals•Very reactive metals that do not occur freely in nature•Often found in salts•Malleable, ductile, good conductors of heat and electricity.•Can explode if they are exposed to water
FAMILIES : Alkaline Earth Metals•Metals•Very reactive•Not found free in nature
FAMILIES : Transition Metals•Ductile And malleable, and conduct electricity and heat •Iron, cobalt, and nickel, are the only elements known to produce a magnetic field
FAMILIES : Rare Earth Metals•Many are man-made
FAMILIES : Halogens•"Halogen" means "salt-former" and compounds containing halogens are called "salts" •Exist in all three states of matter•Usually bond with alkali metals to form basic salts
FAMILIES: Noble Gases•Unreactive•Inert Elements
Metalloids•have Properties of both metals and non-metals•Some of the metalloids are semi-conductors. This means that they can carry an electrical charge under special conditions. This property makes metalloids useful in computers and calculators (“Silicon Valley”)
Non-Metals•Not able to conduct electricity or heat very well•Very brittle•Do not reflect light
Other Metals
•Ductile and Malleable•Many are man-made•Solid with a relatively high density•Opaque
To Summarize:• They are solid (except Mercury)• They are shiny, good conductors of electricity and heat.• They are ductile and malleableMetals
• Brittle (not malleable or ductile)• Poor conductors of both heat and electricityNon-Metals
• Contain properties of both metals and non-metalsMetalloids
