4. Atoms and Elements

Fluorine’s most common isotope is $F^{19}$ (atomic number $9$). How many neutrons are in one atom of $F^{19}$?

An atom has 3 protons and 4 neutrons. Which isotope is it?

Which type of isotope undergoes radioactive decay?

An atom has $17$ protons and $18$ neutrons. Which element (and isotope) is it?

Gold has atomic number 79. How many neutrons are in an atom of the most common isotope, $A^u$ with mass number 197?

Which element is described by an atom that has 19 protons and 20 neutrons?

Which statement best defines a radioactive isotope?

Which element is represented by an atom with 20 protons and 20 neutrons?

Thallium has atomic number 81. How many neutrons are in an atom of thallium-205 (Tl-205)?

Which of the following best describes isotopes?

For an atom with mass number $A$ and atomic number $Z$, how do you determine the number of neutrons ($N$) in the atom?

Which isotope is described by an atom with 11 protons and 12 neutrons?

Which element has a most common isotope that contains 5 neutrons?

Argon has three naturally occurring isotopes, with mass numbers 36, 38, and 40.c. How are they different?

Which term describes atoms of the same element that have different numbers of neutrons?