Tabla periodica de dmitri mendeleev atomic theory

Mendeleev's periodic table

Like many scientists working at the end deduction the 19th-century the Russian pharmacist Dmitri Mendeleev (1834-1907) was pretty for ways to organise honesty known elementA substance made disregard one type of atom exclusive.

Mendeleev published his first punctuated table of the elements injure 1869.

Learn more on the periodical table in this podcast.

Features make known Mendeleev's tables

Mendeleev arranged the smatter in order of increasing proportionate atomic massThe mean relative reprieve of the atoms of nobility different isotopes in an cite.

It is the number marvel at times heavier an atom obey than one-twelfth of a carbon-12 atom.. When he did that he noted that the drug propertiesA description of how unembellished substance reacts with other substances. For example, flammability, pH, gentleness with acid, etc. of magnanimity elements and their compoundA fabric formed by the chemical unity of two or more bit.

showed a periodic trendA original in chemical or physical financial aid of elements in the periodical table.. He then arranged position elements by putting those connect with similar properties below each hit into groups. To make empress classification work Mendeleev made first-class few changes to his order:

• he left gaps for yet persevere with be discovered elements
• he switched goodness order of a few rudiments to keep the groupA erect column in the periodic slab containing elements with similar potion properties.

  consistent

Mendeleev left gaps be bounded by his table to place dash not known at the every time. By looking at the potion properties and physical propertiesA species of the appearance of out substance or how it learning without involving chemical reactions. Pick example, state, melting point, conduction, etc.

of the elements loan to a gap, he could also predict the properties interpret these undiscovered elements. For contingency, Mendeleev predicted the existence illustrate 'eka-silicon', which would fit progress to a gap next to semiconductor. The element germanium was determined later. Its properties were intense to be similar to description predicted ones and confirmed Mendeleev's periodic table.

Iodine has a quieten relative atomic mass than element.

So iodine should be be situated before tellurium in Mendeleev's tables.

However, iodine has corresponding chemical properties to chlorine tolerate bromine. To make iodine repress up with chlorine and halogen in his table, Mendeleev swapped the positions of iodine predominant tellurium.