Solutions: Atomic Structure

Q8.

(a) Name the constituent of an atom which

(i) has zero charge,

neutron

(ii) has the largest charge to mass ratio,

electron

(iii) when removed leaves a different isotope of the element.

neutron

(3)

(b) An s particle is the same as a nucleus of helium, s.
The equation

sssss

represents the decay of thorium by the emission of an s particle. Determine:

(i) the values of X and Y, shown in the equation,

X = 90 - 2 = 88 Y = 229 - 4 = 225

(ii) the ratio of the mass of the radium nucleus to the mass of the alpha particle

225/4 = 56.3 (allow C.E. for value of X from (i))

(3)
(Total 6 marks)