Explain the difference between aldehyde and ketones​

You will remember that the difference between an aldehyde and a ketone is the presence of a hydrogen atom attached to the carbon-oxygen double bond in the aldehyde. Ketones don't have that hydrogen. ... Aldehydes are easily oxidized by all sorts of different oxidizing agents: ketones are not.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.

answer;

18.5 seconds

explanation;

velocity is distance covered per unit time; it is given by displacement divided by time.

thus; time = displacement/velocity

total time = total displacement/velocity

total distance = 5000 meters south

total time = 5000/4.5

                  = 1111.11 seconds

but; 1 minute = 60 sec

thus; 1111.11 /60

                = 18.51 seconds

thus; the time taken is 18.5 seconds