4. Three stable isotopes of oxygen are: 16O 17O 18O. Oxygen has a standard atomic weight of 15.9994 and its atomic number is 8. Which isotope would you consider the most abundant? Identify the mass number, the number of protons, the number of electrons, and the number of neutrons for each isotope.

-Isotope O-16 is the most abundant.

-Isotope O-16 has a mass number of 16 with 8 protons, 8 neutrons, and 8 total electrons.

-Isotope O-17 has a mass number of 17 with 8 protons, 9 neutrons, and 8 total electrons.

-Isotope O-18 has a mass number of 18 with 8 protons, 10 neutrons, and 8 total electrons.

Explanation:

Isotope O-16 makes up more than 99% of the Oxygen on the planet, and you can typically find which elements isotope is the most abundant by rounding its atomic mass to the nearest whole number. In this case you would round 15.9994 to 16 to determine that the the most common isotope of oxygen is O-16.

An elements mass number is equal to the sum of it's protons and neutrons and is used to identify isotopes. So in Oxygen's isotope O-16, the mass number is 16. An elements atomic number corresponds to how many protons are within it's nucleaus, this number does not change, regardless of the mass number. By subtracting the number of protons from the mass number of the isotope we can calculate the number of neutrons in each (16 - 8 = 8 neutrons) (17 - 8 = 9 neutrons) (18 - 8 = 10 neutrons).

In a neutral atom, or an atom with no charge, the number of electrons will equal the number of protons. So by using the atomic number of Oxygen we can calculate the number of electrons for each isotope, which would be 8 for all.