Methylene blue indicates the presence of oxidizing agents because it is oxidized itself by these compounds. When electrons are stripped from methylene blue, the resulting molecule imparts a blue color to the solution--giving a clear sign of a chemical change.
Answer:
+4
Explanation:
In PbO2, oxygen exhibits an oxidation number of -2 (since it's not a peroxide or superoxide):
Let the oxidation number of Pb be x. Then, for the compound to be neutral, the oxidation numbers of all atoms should add up to zero.
⇒ x + (−2) + (−2) = 0
x = +4
So the oxidation no. of Pb is +4.
I hope this helps.
Answer:
3- is the charge and 8 dots on its Lewis dot structure.
Explanation:
Hello there!
In this case, since nitrogen is an element with five valence electrons (electrons on its outer shell), we infer that it needs three bonds to complete the octet, for which its charge, when forming nitride ions is 3-, which means it has received three electrons. Thus, when drawing the Lewis dot structure, it is evident that is will have 5+3 = 8 dots due to the electron reception.
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Molecules are made up by chemically bonding two or more atoms of the same element or different elements, they don’t have charge, and the atoms are bonded by covalent bonds. <span>Lattices have a three- dimensional ordered arrangement of basic units (that can be an atom, molecule or an ion). Lattices are crystalline structures with these repeated basic units. When ions joined with ionic bonds, they form ionic crystals. The formula unit tells us that aluminium hydroxide has a crystal structure made from molecules. </span>
