The atmosphere is a mixture of gasses.
One of the basic building blocks of matter, which cannot be broken down by chemical means is an element.
The first chemical element is hydrogen (atomic number is 1) and the last is oganesson (atomic number is 118).
Elements are scheduled in Periodic table, ordered by their atomic number.
Other example, krypton is a chemical element with symbol Kr and atomic number 36.
Krypton has 36 electron and 36. It is noble gas (group 18).
Noble gases are in group 18: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). They have very low chemical reactivity.
More about chemical element: brainly.com/question/28376204
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For the first one it’s 69 just count the little lines from the side.
Explanation:
I think 1) acidic solution
2) basic solution.
Answer is 2KClO3 3O2 + 2KCl
