Which sequence is an example of radioactive decay?

a. the nuclei of two hydrogen atoms fuse together, forming a helium nuclide.
b. a calcium atom gives its electrons to two fluorine atoms, forming a formula unit of calcium fluoride.
c. a polonium isotope becomes a lead isotope when the polonium nuclide emits two protons and two neutrons.
d. energy from an electric current splits a water molecule into two hydrogen atoms and one oxygen atom.

option C. A polonium isotope becomes a lead isotope when the polonium nuclide emits two protons and two neutrons.

Explanation:

1) Radioactive decay is the spontaneus process in which unstable nucleii lose enery by emitting radiation.

2) There are three kinds of radiations:

i) α radiation, or α partilces. These are helium nuclei: two protons and two neutrons, which is what the option C. states.

ii) β radiation or β particles. These are electrons in fast motion.

iii) γ ratiation or γ rays. They are high energy radiation, without mass and charge.

3) This is a sketch for the radiactive decay of a polonium isotope becoming a lead isotope by emitting two protons and two neutrons, following the statement of the option C) :

polonium-210 → lead-206 + helium nucleous (two protons and two neutrons)

option C. A polonium isotope becomes a lead isotope when the polonium nuclide emits two protons and two neutrons.

Explanation:

1) Radioactive decay is the spontaneus process in which unstable nucleii lose enery by emitting radiation.

2) There are three kinds of radiations:

i) α radiation, or α partilces. These are helium nuclei: two protons and two neutrons, which is what the option C. states.

ii) β radiation or β particles. These are electrons in fast motion.

iii) γ ratiation or γ rays. They are high energy radiation, without mass and charge.

3) This is a sketch for the radiactive decay of a polonium isotope becoming a lead isotope by emitting two protons and two neutrons, following the statement of the option C) :

polonium-210 → lead-206 + helium nucleous (two protons and two neutrons)

d) physical means can be used to separate the components of air.