Levels of Organization. ATOMS Smallest part of matter NON-living.
Organization of Matter
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Transcript of Organization of Matter
Organization of Matter
S1-2-03 Define element and identify symbols of some common elements.
S1-2-06 Investigate the development of the periodic table as a method of organizing elements.
S1-2-08 Relate the reactivity and stability of different families of elements to their atomic structure.
Vocabulary & People
Period Non-metals Group
Family Alkali metals Earth metals
Chalcogens Halogens Noble gases
Mendeleev
Element Modern Symbols Alchemist Symbols Dalton Symbols
Antimony Sb
Arsenic As
Bismuth Bi
Carbon C
Copper Cu
Gold Au
Iron Fe
Lead Pb
Mercury Hg
Silver Ag
Sulpher S
Tin Sn
Zinc Zn
Elemental symbols originated from a Greek or Latin root word
Mendeleev (1870)• Russian scientist and professor• Arranged the 63 elements by atomic mass• Noticed a repetition of properties (periodicity)
• Called the pattern of properties “Periodic Law”
Mendeleev (correctly) predicted the mass of elements yet to be discovered and left spaces open for them
Modern Periodic Law:“The properties of elements are a periodic function of
increasing atomic number”
We know now that most element properties are due to the number of valence electrons – luckily electron and proton numbers are equal
Moseley (1913)Experiments showed proton number was a better method to organize the elements.
• Repetition of properties (periodicity) became more clear
The Periodic Table contains metals and non-metals.
A staircase separates metals from non-metals.
M e t a l sNon- metals
Rows of the periodic table are called periods. • Elements in periods do not have similar properties
Left to rightElements change from metals to non-metals
per
iod
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Non-metalElement with
properties opposite to those of metals
(brittle, dull…)
Columns of the periodic table are called groups. • Elements in groups have similar properties
A family is a group with a specific name:
• Alkali metals• Alkaline Earth metals• Chalogens• Halogens• Inert (noble) gases
GROUP
Family names and locations need to be memorized
Older tables have an old label system for columns with Roman numerals – new tables just number them 1 through 18
Hydrogen*• Group 1 • Non-metal gas• 1 valence electron• Simplest atomic structure - only 1 e- and 1 p+
• Highly chemically reactive
The placement of hydrogen is only because of its structure - 1 proton… Sometimes a table will have it raised above the Alkali Metals to avoid confusion
What trends (“periodicity”) have you found?
The Octet Rule of Chemical Reactions• Atoms with a FULL outer orbit are very stable
Chemical reactions happen when atoms work together to try to get a full valence orbit
Atoms will acquire a full outer shell in 3 ways:• Give away an e- to another atom• Take an e- from another atom• Share an e- with another atomWe’ll skip this one until next year
Sodium atom:11 p+
11 e-
Na
Sodium ion:11 p+
10 e-
Na +
+
Once a neutral atom gains or loses e- to be more stable it is called an ion
Chlorine atom:17 p+
17 e-
Cl
Chlorine ion:17 p+
18 e-
Cl -
-
Notice the ion has a charge associated with it based on the number of e- lost or gained
Calcium atom:20 p+
20 e-
Ca
Calcium ion:20 p+
18 e-
Ca 2+
2+
Nitrogen atom:7 p+
7 e-
N
Nitrogen ion:7 p+
10 e-
N 3-
3-
The LESS electrons needed, the GREATER the chemical reactivity of the element
A Chemical Reaction Movement of electrons between combining
atoms that results in the formation of a NEW substance.
Incr
easi
ng R
eacti
vity
Working together to become more stable is what binds atoms (now called ions) together to make compounds.
+ -
explosive metal toxic gas
A new substance is formed
Salt!
CAN YOU ANSWER THESE QUESTIONS?
S1-2-06How is the Periodic Table organized for the elements and what trends exist?
S1-2-03What are the symbols of the first 20 elements and other common ones?
S1-2-08Why do families react differently during chemical reactions?
Vocabulary & People
Non-metals Period Group
Family Alkali metals Earth metals
Chalcogens Halogens Noble gases
Mendeleev