Explanation:
When the name of an atom is given with a number, that number represents the atomic mass of the element. So, in this case, gallium-69 means that this gallium atom has an atomic mass of 69.
To calculate the number of electrons, protons and neutrons it is important to remember a few definitions:
- Atomic number: it is the number of electrons (and protons, the number is the same) of an atom. We can find this number in the periodic table.
- Atomic mass (Mass number): it is the sum of protons and neutrons that an atomic nucleus has.
A) Gallium-69:
Atomic number: 31
Atomic mass: 69
So, the number of electrons and protons is the same as the atomic number:
Electrons: 31
Protons: 31
Then, by making a subtraction between atomic mass and atomic number we obtain the number of neutrons:
Neutrons: atomic mass - atomic number = 69 - 31 = 38
We can do this with the other elements.
B) Fluorine-23:
Atomic number: 9
Atomic mass: 23
Electrons: 9
Protons: 9
Neutrons: 23 - 9 = 14
C) Titanium-48:
Atomic number: 22
Atomic mass: 48
Electrons: 22
Protons: 22
Neutrons: 48 - 22 = 26
D) Tantalum-181:
Atomic number: 73
Atomic mass: 181
Electrons: 73
Protons: 73
Neutrons: 181 - 73 = 108
