Question

For each of the isotopes listed, provide the following.

isotope (1):	5321Sc
isotope (2):	74Be
isotope (3):	5523V

Using the band of stability, predict the type(s) of decay for the following nuclei. (Select all that apply. Select "does not decay" if the nucleus is stable.)

(alpha emission, beta⁺ emission, beta⁻ emission, electron capture, does not decay)

isotope (1):    ⁵³₂₁Sc

isotope (2):    ⁷₄Be

isotope (3): ⁵⁵₂₃V

Write the nuclear reaction that each nucleus would likely undergo based on its stability. (Enter your answer in the form

A	X
Z

Omit states-of-matter from your answer.)

isotope (1):    ⁵³₂₁Sc

isotope (2):    ⁷₄Be

isotope (3):    ⁵⁵₂₃V

Answer 1

• The band of stability is a graph drawn between the number of protons in the x-axis and number of neutrons in the y-axis.This graph is used to predict the stability and hence the possibility of decay of the isotopes of elements.
• For elements with atomic number less than 20, the isotopes are stable if they have an n/p ratio (ratio of the number of neutrons to protons) equal to 1
• For elements with higher atomic number,the type of decay depends on it's deviation from the stability belt.(The graph has been shown in the image attached)​.

Isotope 1

• is an isotope of the element scandium.
• Its mass number is 53 which is the sum of the number of neutrons and electrons.
• Atomic number(number of protons or electrons)is 21
• So it has 21 protons and 32 neutrons in its nucleus and also 21 electrons revolving around the nucleus.
• The n/p ratio is 1.523.There is more number of neutrons, so this isotope undergoes electron or emission for approaching stability and the equation is given below:
• 
• The new n/p ratio is 1.41

Isotope 2

• has 4 electrons,4 protons, and 3 neutrons
• The n/p ratio is 0.75, which is less than 1.So this isotope lies below the stability line in the stability graph.
• It will undergo electron capture or positron emission to increase the n/p ratio   
• Electron capture is as given:
• Hence the n/p ratio increases to 1.33 and the daughter atom is stable.
• Positron emission take place as below-
• 
• Positron is also known as

Isotope 3

• has 23 electrons,23 protons and 32 neutrons
• The n/p ratio is 1.39, which is greater than 1.So this isotope lies above the band of stability graph.
• It will undergo electron decay as below :
• 
• n/p ratio decreases to 1.29