Why mendeleev placed tellurium before iodine

Your Email Address:. Index Newest Popular Best. New Player Log In. Newest Questions Post a Question Search All Questions Please cite any factual claims with citation links or references from authoritative sources. Editors continuously recheck submissions and claims. Archived Questions Goto Qn. Why are Tellurium and Iodine the wrong way round on the periodic table? KayceeKool Answer has 11 votes.

Wiki User. Iodine has a lower relative atomic mass than tellurium, meaning it should come before tellurium following Mendeleev's rule.

However, in order to place iodine with the elements that consisted of similar properties, he had to put it after tellurium. Thus breaking his own rule. Mendeleev was born in the village of Verkhnie Aremzyani, near Tobolsk in Siberia. Placing iodine covered in a warm place could cause sublimation to a cool spot on the container - if the temperature is even on the container walls, if the temperature is warm enough the violet colour of gaseous iodine may be visible.

When iodine is placed in potato juice it turns dark purple to black. It's the starch in potatoes that reacts with the iodine. LOM can be used as x-ray contrast media in patients allergic to iodine. If the leaf is tested for starch using iodine, and the iodine turns blue-black in colour it shows that photosynthesis has taken place. In the past, manganese was erroneously located. Place a few drops of iodine on the foods you are testing and if they contain starch the iodine drops will turn dark purple.

The periodic table is an array of various elements. Iodine is an element. Hence it finds it place on the periodic table. Yes, the speed at which you absorb Iodine is determined by how deficient your body is. It is usually recommended to place spot of iodine the size of a silver dollar on your stomach. If the Iodine disappears in less than 24 hours, then you are deficient.

For example, Mendeleev's original table postulated an element "ekasilicon" occupying the place of the modern element germanium, which had not yet been isolated at the time. Yes iodine is an element. It has a reserved place in the periodic table with an atomic number This means the number of protons within the nucleus of iodine will be But an Iodine atom has one more proton than a Tellurium atom.

The Periodic Law states that the physical and chemical properties of the elements recur in a systematic and predictable way when the elements are arranged in order of increasing atomic number. Many of the properties recur at intervals.

Mendeleev developed a Periodic Table of elements wherein the elements were arranged on the basis of their atomic mass and also on the similarity on chemical properties. On this basis he formulated a Periodic Law, which states that 'the properties of elements are the periodic function of their atomic masses'. To make iodine line up with chlorine and bromine in his table, Mendeleev swapped the positions of iodine and tellurium.

Mendeleev's periodic table became widely accepted because it correctly predicted the properties of elements that had not yet been discovered. Iodine has a lower atomic mass than tellurium Tellurium is a chemical element with the symbol Te and atomic number It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens.

Tellurium has been used to vulcanise rubber, to tint glass and ceramics , in solar cells, in rewritable CDs and DVDs and as a catalyst in oil refining. It can be doped with silver, gold, copper or tin in semiconductor applications. Here we'll discuss a few actual rare metals, present in the earth in miniscule amounts but which have important applications nonetheless. The rarest stable metal is tantalum. The rarest metal on earth is actually francium, but because this unstable element has a half life of a mere 22 minutes, it has no practical use.

With this strategy, Mendeleev could organize and rearrange material until patterns emerged. In , Russian chemist and teacher Dmitri Mendeleev — published a periodic table of the elements. The following year, German chemist Lothar Meyer independently published a very similar table.

Mendeleev is generally given more credit than Meyer because his table was published first and because of several key insights that he made regarding the table.

Mendeleev was writing a chemistry textbook for his students and wanted to organize all of the known elements at that time according to their chemical properties. He famously organized the information for each element on to separate note cards that were then easy to rearrange as needed. He discovered that when he placed them in order of increasing atomic mass, certain similarities in chemical behavior repeated at regular intervals.

In the Figure 2 , atomic mass increases from top to bottom of vertical columns, with successive columns going left to right. As a result, elements that are in the same horizontal row are groups of elements that were known to exhibit similar chemical properties.

Notice that tellurium is listed before iodine even though its atomic mass is higher. Mendeleev reversed the order because he knew that the properties of iodine were much more similar to those of fluorine F , chlorine Cl , and bromine Br than they were to oxygen O , sulfur S , and selenium Se.