2. Atoms & Elements

Which of the following elements has atoms with the greatest average number of neutrons?

Magnesium has three naturally occurring isotopes: 24Mg, 25Mg, and 26Mg. If the atomic mass of magnesium is 24.305 u and the masses of the isotopes are 23.985 u (24Mg), 24.986 u (25Mg), and 25.983 u (26Mg), what is the fractional abundance of 24Mg if the abundances of 25Mg and 26Mg are 0.10 and 0.11, respectively?

What are the atomic number and mass number for the carbon isotope with seven neutrons?

Which property distinguishes isotopes of the same element from each other?

Which of the following are the stable isotopes of nitrogen?

How do the isotopes of an element differ from each other?

Which of the following isotopes has the same number of neutrons as nitrogen-15 (N-15)?

How many protons does the isotope lithium-8 have?

Which of the following is the number of neutrons in the most abundant isotope of tungsten (W)?

Which of the following is the correct nuclear symbol for the isotope of beryllium with mass number a = 10?

How many neutrons are present in an atom of silicon-30?

An element has two isotopes, X and Y, with mass numbers of 52.0 and 53.0 respectively. The relative atomic mass is 52.2. What is the percentage abundance of isotope X?

Which of the following isotopes is not possible?

Which of the following best describes how radioactive isotopes differ from stable isotopes?