4. Atoms and Elements

How many neutrons are in an atom of magnesium-25 ($Mg-25$)? (Atomic number of Mg is 12.)

Which element is represented by an atom with 3 protons and 4 neutrons?

How do isotopes of a given element differ from one another?

Indicate if the atoms in each pair have the same number of protons, neutrons, or electrons. (4.4, 4.5) c. ⁴⁰₁₈Ar, ³⁹₁₇Cl

Tin has atomic number 50. How many neutrons are in an atom of tin-120 (Sn-120)?

An atom has 14 protons and 15 neutrons. Which element is it (and what is the isotope’s mass number)?

Which pair of nuclide notations represent isotopes of the same element?

Isotopes of an element differ in their:

A period 5 transition metal has 51 neutrons. If the element is yttrium, what is the mass number of this isotope? (Atomic number of Y is $39$.)

Which element is described by an atom that has 35 protons and 45 neutrons?

Which of the following correctly represents a bromine isotope that has 46 neutrons?

Copper has atomic number 29. How many neutrons are in an atom of the isotope copper-63?

How many neutrons are in a ${\mathrm{He}}^4$ atom?

Which element is represented by an atom that has 9 protons and 10 neutrons?

In terms of subatomic particles, how does one isotope of an element differ from another isotope of the same element?