Dimitri Mendeleev was the first to put elements together on a table. He knew there were elements missing but he noticed a trend in some of the elements known at the time. Sodium, Lithium and other alkali metals all have the same properties so he put them under the same column and created other columns with similar attributes (Halogens, Noble gases, Alkaline earth metals). Over the years, new elements were discovered and put into the rough outline that Mendeleev created.
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Answer:
explanation and image attached
Explanation:
Our aim is to draw a structure of XeO2F2 whith the least formal charges. We must remember that the compound has 34 valence electrons.
To obtain the least formal charges then Xe must have a total of twelve electrons on its valence shell instead of eight.
The other atoms around the central Xe atom are arranged as shown in the image attached.
Image Credit: UCLA
Answer:
Cu(s) + 2AgNO3(aq)→Cu(NO3)2(aq)+2Ag(s)
This chemical equation means:
One mole of solid copper plus two moles of aqueous silver nitrate produce one mole of copper(II) nitrate plus two moles of solid silver.
This is a single replacement reaction in which the metal copper replaces the metal silver.