Answer:
9000 BC
Explanation:
Although various copper tools and decorative items dating back as early as 9000 BCE have been discovered, archaeological evidence suggests that it was the early Mesopotamians who, around 5000 to 6000 years ago, were the first to fully harness the ability to extract and work with copper.
Answer:
C
) 2, 1, 2
Explanation:
The given reaction is synthesis reaction in which lithium and bromine react to form lithium bromide.
Chemical equation:
Li + Br₂ → LiBr
Balanced chemical equation:
2Li + Br₂ → 2LiBr
Step 1:
Li + Br₂ → LiBr
left hand side Right hand side
Li = 1 Li = 1
Br = 2 Br = 1
Step 2:
Li + Br₂ → 2LiBr
left hand side Right hand side
Li = 1 Li = 2
Br = 2 Br = 2
Step 3:
2Li + Br₂ → 2LiBr
left hand side Right hand side
Li = 2 Li = 2
Br = 2 Br = 2
Glacier. Since glazier is the coldest out of all of them.
Hence, 5.1 * 10^-11 alpha particles is being emitted each second by the sample.
<h3>What is half life?</h3>
The term half life is the time taken for only half of the original amount of radioactive nuclides to remain.
Thus, we have that the half life is 432.2 years or 1.36 * 10^10 s.
k = 0.693/ 1.36 * 10^10 s
k = 5.1 * 10^-11 alpha particles per second.
Learn more about alpha particles:brainly.com/question/2288334
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By convention, elements are organized in the periodic table, a structure that captures important patterns in their behavior.