Answer:
a mixture in which the composition is uniform throughout the mixture.
Explanation:
Answer:
A
Explanation:
it's the sum of the masses of all the atoms in the molecule
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The elements are arranged by their atomic number but are also grouped by what type of element they are.
For example, metals, non metals, metalloids, and noble gasses will be grouped with elements that match them.
Hope this makes sense!
Number 18 is correct, number 19 is the particles speed up and the substance expands, and number 20 is decrease in volume