2. Atoms & Elements

How many neutrons are present in the most abundant isotope of oxygen?

Which of the following is the number of neutrons in the most abundant isotope of argon (argon-40)?

What is the mass number for lithium?

Antimony has two naturally occurring isotopes: Sb-121 with a mass of 120.904 amu and a natural abundance of 57.21%, and Sb-123. If the atomic mass of antimony is 121.760 amu, what is the mass of Sb-123?

Which of the following main isotopes of carbon exist naturally as ions?

Which pair of atoms are isotopes of each other?

Which pair below describes isotopes of the same element?

Beryllium has several isotopes. How many neutrons are present in the most abundant isotope of beryllium, Be-9?

Which of the following isotopes has 45 neutrons?

Isotopes of an element will always differ in:

Which of the following correctly describes the conditions under which two atoms are considered different isotopes of the same element?

A diagram shows three atoms, each with 6 protons but different numbers of neutrons. What element is represented by these isotopes?

How many neutrons are present in the isotope lithium-8?

Astatine-210 is one of the most stable isotopes of astatine. How many neutrons are present in an atom of astatine-210?

How many protons are present in an atom of strontium-90?