The periodic table is one of the most important tools in the history of chemistry. It describes the atomic properties of every known chemical element in a concise format, including the atomic number, atomic mass and relationships between the elements. Elements with similar chemical properties are arranged in columns in the periodic table.
The table thus is a quick reference as to what elements may behave the same chemically or which may have similar weights or atomic structures.
Hope this answer helps you
Answer : The 
must be administered.
Solution :
As we are given that a vial containing radioactive selenium-75 has an activity of 
.
As, 3.0 mCi radioactive selenium-75 present in 1 ml
So, 2.6 mCi radioactive selenium-75 present in 
Conversion :
Therefore, the must be administered.
140 s. It would take 140 s to swim 0.150 mi
.
<em>Step 1</em>. Convert the <em>time to seconds</em>
Time = 14 min × (60 s/1 min) + 34.56 s = 840 s + 34.56 s = 874.56 s
<em>Step 2</em>. Convert <em>miles to metres
</em>
Distance = 0.150 mi × (1609.3 m/1 mi) = 241.4 m
<em>Step 3.</em> Calculate the <em>time to swim 241.4 m</em>
Time = 241.4 m × (874.56 s/1500 m) = 140 s
(<em>As of 2012, the men’s freestyle record for 1500 m was 14:31.02</em>.)
