Question

multiple choice 2 points
when a neutron inside the nucleus of an atom breaks apart into a proton and an electron, the electron is ejected from the nucleus at high speed. this type of decay is
known as____decay.
alpha
beta
gamma
primary
what is the atomic number of the missing element (the number of protons)?
235 92u + 1 0n → 95 37rb + □ + 2·1 0n
35
55
45
65

Explanation:

Step1: <Conservation of atomic number>

In a nuclear reaction, the sum of atomic numbers on the left - hand side is equal to the sum of atomic numbers on the right - hand side.
The atomic number of \(^{235}_{92}U\) is \(Z_{U}=92\), the atomic number of \(^{1}_{0}n\) is \(Z_{n}=0\), the atomic number of \(^{95}_{37}Rb\) is \(Z_{Rb} = 37\), and the atomic number of \(^{1}_{0}n\) (in \(2^{1}_{0}n\)) is \(Z_{n}=0\). Let the atomic number of the unknown element be \(Z\).
Using the conservation of atomic number: \(Z_{U}+Z_{n}=Z_{Rb}+Z + 2Z_{n}\)

Step2: <Solve for \(Z\)>

Substitute the values: \(92+0 = 37+Z+2\times0\)

$$Z=92 - 37$$

$$Z = 55$$

Answer:

55