As a trend or pattern, the atomic radius decreases as you go left to right across the period, but increases as you go down a particular group.
Mutation. Called this because the other possible answers do not equal a copying error, mutations affect the outcome.
You can have a solution of hydrogen peroxide that might say 10% that means that 10% per mass of the hydrogen peroxide solution is the hydrogen peroxide the rest is water.
concentration is the amount of mass in the solution eg 5gdm-3
hope that helps
The answer is 18 you multiply wavelength (6) times frequency (3)