Answer: [Kr] 5s24d10 is the element Cadmium, Cd. It has 48 electrons.
Answer:






Explanation:
In the first nucleus we are told that there are two protons and one neutron. Let us remember that the mass number = number of protons + number of neutrons.
This implies that, for the first specie the mass number is 3, for the second specie the mass number is 6 and the third specie has a mass number of 7 and so on. The mass number is indicated as a superscript.
The atomic number is the number of protons in the nucleus of the atom and helps us to identify the atom. It is always written as a subscript as shown.
The formula for kinetic energy is listed below...
Kinetic Energy = 0.5*mass*velocity^2
As we can see, if we increase the mass of the object, the kinetic energy will increase.