To calculate the number of protons, neutrons, and electrons in barium (Ba) with a mass number of 136 and polonium (Po) with a mass number of 209, we can refer to the periodic table for the atomic numbers of these elements.
Barium (Ba)
Barium has an atomic number of 56, which means it has 56 protons. In a neutral atom, the number of electrons is equal to the number of protons. Therefore, barium also has 56 electrons.
The number of neutrons can be calculated by subtracting the atomic number from the mass number:
Neutrons = Mass number - Atomic number
Neutrons = 136 - 56 = 80
So, for barium-136:
- Protons: 56
- Neutrons: 80
- Electrons: 56
Polonium (Po)
Polonium has an atomic number of 84, meaning it has 84 protons and, in a neutral atom, 84 electrons as well.
To find the number of neutrons for polonium-209, we again use the formula:
Neutrons = Mass number - Atomic number
Neutrons = 209 - 84 = 125
Therefore, for polonium-209:
- Protons: 84
- Neutrons: 125
- Electrons: 84
In summary, we have:
- Barium-136: 56 protons, 80 neutrons, 56 electrons
- Polonium-209: 84 protons, 125 neutrons, 84 electrons