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Dobereiner’s triads were a type of classification system. A triad is a set of three elements with similar properties.

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A Russian chemist and teacher that published a table of the elements

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Why did scientists need to have a way to organize the elements?

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Why did scientists need to have a way to organize the elements?

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Scientists needed to have a logical way to organize the elements.

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A Russian chemist and inventor, created the first version of the periodic table.

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They are poor conductors of heat and electric current.
They are gases at room temperature and some are solids.

How are these different from metals?
They are completely opposite of metals.
Metals are good conductors and non-metals aren’t.
Metals are mostly solid at room temperature.
Metals are malleable.
Metals can reflect light.

Where do we find non-metals on the periodic table?
You can find non-metals in the upper right corner of the periodic table.

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How does the number of metals compare to the number of elements?

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How does the number of metals compare to the number of elements?

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Metals take up 80% of the periodic table

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What problem is there with organizing elements by increasing Atomic Mass?

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What problem is there with organizing elements by increasing Atomic Mass?

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The chemical properties of the elements were a more accurate way to organize the elements instead of by Atomic Mass

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What problem isn’t there with organizing elements bY increasing atomic mass

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What problem isn’t there with organizing elements bY increasing atomic mass

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Mendelev didn’t know that the atoms of each element contain a unique number of protons

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Why did scientists need to have a way to organize the elements?

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Why did scientists need to have a way to organize the elements?

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They needed a way to be able to know if there was a limit to the number of elements or if they had discoveredall of the elements. They had also discovered many elements in a short period, and needed a way to organize them.

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Where do we find metaloids on the periodic table?

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Where do we find metaloids on the periodic table?

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They are the seven elements along the stair case

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Describe the process he used to create his table

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Describe the process he used to create his table

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He wrote the properties of each element on a separate notecard. This allowed him to move the cards around until he found an organization that worked.

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Describe the process he used to create his table.

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Describe the process he used to create his table.

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He wrote elements on notecards and moved them around until he found a pattern.

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Where, in general, do we find metals on the periodic table

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Where, in general, do we find metals on the periodic table

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Metals can be found in the entirety of the D and F blocks, the majority of the S block apart from 1s2, and in the left part of the P block up to the stairstep. (Group 13 apart from Boron, Group 14 apart from Carbon, Silicon, Germanium, etc)

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Where do we find the metalloids on the periodic table?

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Where do we find the metalloids on the periodic table?

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The metalloids are bordering the stair case. The stair case starts between B and Al and move it’s way down and stops between Pb and Bi

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How did early scientists group elements?

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How did early scientists group elements?

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They used triads to group the elements. A triad is a set of three elements with similar properties.

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Chlorine, bromine, and iodine form one triad. They look different but have similar chemical properties.

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Mendeleev arranged the elements in his periodic table in order of increasing  atomic mass.

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Boran, silicon, germanium, arsenic, antimony, tellurium, and polonium

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How did early scientists group elements?

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How did early scientists group elements?

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Dobereiner published a classification system that grouped elements into triads.

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He arranged the elements in his periodic table in order of increasing atomic mass.

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How did Moseley reorganize the periodic table

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How did Moseley reorganize the periodic table

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He arranged the elements in order of increasing atomic number

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They are poor conductors of heat and electric current. They are also gases at room temperature.

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A group of 3 elements with similar chemical properties.

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What was significant about the spaces on his table?

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What was significant about the spaces on his table?

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He knew there would be elements to fill the missing spaces, but they had not been discovered yet.

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When elements are arranged in order of increasing atomic number, there is a periodic religion of their physical and chemical properties

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What was significant about the spaces (or question marks) on his table?

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What was significant about the spaces (or question marks) on his table?

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He predicted that elements would be discovered to fill those spaces, and he predicted what their properties would be based on their locations in the table.

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How did Moseley reorganize the periodic table?

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How did Moseley reorganize the periodic table?

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He reorganized it by order of increasing Atomic Number

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What pattern did Dobereiner notice in his triads?

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What pattern did Dobereiner notice in his triads?

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One element in each triad tended to have properties with values that fell midway between those of the other two elements.

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What was the problem with using triads to categorize elements?

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What was the problem with using triads to categorize elements?

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Needed a way to organize it into different groups numerically

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How does IUPAC organize the columns on the periodic table 

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How does IUPAC organize the columns on the periodic table 

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It is organized by metals, mataliods, non metals

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High luster or sheen (caused by the ability to reflect light)
Solid at room temperature (except for Mercury, Hg)
Ductile- can be drawn into wires
Most are malleable- can be hammered into thin sheets without breaking

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How do the properties of metalloids compare to metals and non metals?

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How do the properties of metalloids compare to metals and non metals?

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Metalloids are Different but can also be the same at conducting heat and electricity as a metal but can also be as poor at conducting heat and electricity as a nonmetal

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How do elements change as you move from left to right within a row on the periodic table

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How do elements change as you move from left to right within a row on the periodic table

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Across a period, the properties of elements become less mattalic and more non metallic

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What pattern did Dobereiner notice in his triads?

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What pattern did Dobereiner notice in his triads?

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One element in each trail tended to have priorities with values that fell midway between those of the other two elements

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How does the number of metals compare to the total number of elements?

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How does the number of metals compare to the total number of elements?

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Most elements on we periodic table are metals—about 80%

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What physical state are most metals at room temperature? What’s the exception?

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What physical state are most metals at room temperature? What’s the exception?

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They are solids except for Mercury (Hg).

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When elements are arranged in order of increasing Atomic Number, there is a periodic repetition of their physical and chemical properties.

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What was the problem with using triads to categorize elements?

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What was the problem with using triads to categorize elements?

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All of the known elements could not be grouped into triad.

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Where (in general) do the find metals on the periodic table?

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Where (in general) do the find metals on the periodic table?

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In general you would find them in S-block, D-block and F-block

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How does the IUPAC organize the columns on the Periodic Table

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How does the IUPAC organize the columns on the Periodic Table

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They numbered the groups from left to right 1-18

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Chlorine, Bromine, Iodine. They have similar chemical properties.

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How do elements change as you move from left to right within a row on the periodic table?

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How do elements change as you move from left to right within a row on the periodic table?

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They become less metallic and more nonmetallic

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How are non-metals different from metals?

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How are non-metals different from metals?

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Metals
Good conductors of heat and electricity
Solid at room temperature
Most are ductile(can be turned into a wire)
Malleable

Nonmetal
Poor conductors of heat and electricity
Gas at room temperature
Few are solid at room temperature
Solid non-metals are brittle

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*Metals are good conductors for heat and electrical currents
*They have the ability to reflect light
*Many are ductible, which means they can be drawn into wires
*Most are malleable, which means they can be hammered into thin sheets without breaking

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How do the properties depend on conditions. Give an example 

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How do the properties depend on conditions. Give an example 

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The reactivity of metalloids depend on the elements with which their reacting with. For example silicon is a metallic luster yet it is not an inefficient conductor.

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Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Polonium

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What physical state are most metals at room temperature? What’s we exception?

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What physical state are most metals at room temperature? What’s we exception?

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They are all solids at room temperature, except for mercury, mercury is a liquid at room temperature.

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Where (in general) do we find nonmetals on the periodic table?

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Where (in general) do we find nonmetals on the periodic table?

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The top right area including the noble gases.