An atom 23892X decays by alpha particle emission to give an atom Y. The atomic number and mass number of Y are
Answer Details
An alpha particle consists of two protons and two neutrons, and it is symbolized by the Greek letter alpha (α). When an atom emits an alpha particle, it loses two protons and two neutrons, which means that its atomic number decreases by 2 and its mass number decreases by 4.
In the given question, the parent atom is X with a mass number of 238 and atomic number of 92. It decays by alpha particle emission, which means it loses two protons and two neutrons. Therefore, the daughter atom Y will have a mass number of 238-4=234 and an atomic number of 92-2=90.
So, the atomic number and mass number of the daughter atom Y are 90 and 234, respectively. Therefore, the correct option is: "90 and 234 respectively".