Answer:
Physical
Explanation:
The change of density alone is a physical change, but there might be some chemical change that results in physical change. For example: Burning a piece of paper will definitely change the density of the paper as some of its content is being changed into smoke which is a gas. So there will be a change in volume which in turn leads to change in density. Therefore, the change of density alone is a physical change, but the change might occur due to another chemical change.
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Answer:
Y is a gamma ray in a nuclear equation, which y equals 0.
Metals=Reactivity increases as we move through the elements in the period table from top to bottom, and left to right. Nonmetals=Reactivity increases as we move through the elements in the periodic table, as we move from bottom to the top, and right to left. Since reactivity of nonmetals increases going up the periodic table, oxygen is therefore the most reactive nonmetal in the group. So, the answer is oxygen