Most elements on group 18 are the Noble Gases. They already have a complete last level with 8 electrones. Actually they can form compounds but only on the lab and they will not even last half a second.
The answer is A. planning a hiking trip
A topographical map would not help studying plant growth over time unless you are looking for a better altitude to plant said plants.
A topographical map would not help studying rainfall for one year unless your location was <em>really</em> so high or low that it affected your weather
And most of all, a topographical map would not be useful for planning a cuise across the Atlantic Ocean because the elevation of the sea is zero!
A topographical map <em>would</em> be useful for planning a hiking trip because there are many factors and details that a hike should have. Which includes height, distance, paths, and elevation.
<u>Answer:</u> The mass of solution having 768 mg of KCN is 426.66 grams.
<u>Explanation:</u>
We are given:
0.180 mass % of KCN solution.
0.180 %(m/m) KCN solution means that 0.180 grams of KCN is present in 100 gram of solution.
To calculate the mass of solution having 768 mg of KCN or 0.786 g of KCN (Conversion factor: 1 g = 1000 mg)
Using unitary method:
If 0.180 grams of KCN is present in 100 g of solution.
So, 0.768 grams of KCN will be present in = 
of solution.
Hence, the mass of solution having 768 mg of KCN is 426.66 grams.
Isomers, when its the same chemical formula, but rearranged differently.
Yahoo has the answer to that question. because i looked it up on yahoo..
