RADIOACTIVITY, MODES OF RADIOACTIVE DECAY & RADIOACTIVE DECAY LA

Sir Kris'

Henri Becquerel

Who discovered the phenomenon later known as radioactivity in 1896?

Uranium salts exposed photographic plates without the presence of light

What observation led Henri Becquerel to the discovery of radioactivity?

The emission was spontaneous and continuous.

What were the key characteristics of the emission observed by Becquerel?

No, he documented the scientific observations before the phenomenon was named radioactivity.

Henri Becquerel originally identify the phenomenon as radioactivity?

Marie and Pierre Curie

Who coined the term “radioactivity”?

Polonium and Radium

Which two radioactive elements were identified by the Curies?

That radioactivity is an atomic property

What major scientific principle about radioactivity did the Curies prove?

radioactivity

The spontaneous emission of energy and/or particles from an unstable atomic nucleus.

No, it is spontaneous and occurs without an external trigger.

Is radioactivity triggered by external factors?

Nuclear—it originates in the atomic nucleus, not from orbital electrons.

Is radioactivity a nuclear or electron-based process?

It is predictable statistically, but not individually for a single atom

Is radioactive decay predictable?

Due to an imbalance between forces within the nucleus.

Why are some atomic nuclei unstable?

The nuclear strong force and electrostatic proton repulsion.

Which two forces must be balanced for nuclear stability?

Having too many or too few neutrons can make the nucleus unstable.

How does neutron number affect nuclear stability?

Instability represents stored nuclear energy.

What important concept is associated with nuclear instability?

A stable nucleus has a balanced internal force system, while an unstable nucleus does not.

What distinguishes a stable nucleus from an unstable nucleus?

Energy already stored inside the atomic nucleus.

What is the source of the energy emitted during radioactive decay?

Mass–energy equivalence, as described by Einstein.

What physical principle explains how mass is converted into energy in radioactive decay?

Very small mass differences result in large energy release.

How do small mass differences affect energy release?

No, the energy originates within the nucleus itself.

Is the energy released during radioactive decay added from an external source?

Radioactive Decay

A process in which an unstable nuclide transforms into a more stable element by emitting radiation.

From the atomic nucleus

From where does radioactive decay originate in the atom?

To achieve a more stable nuclear configuration.

What is the purpose of radioactive decay for an unstable nucleus?

radioactive isotope

an isotope with an unstable nucleus that emits radiation to become more stable.

They have too many neutrons or protons causing unstable nuclear forces.

Why are some isotopes radioactive?

Unstable forces within the nucleus due to an improper neutron-to-proton ratio.

What condition inside the nucleus leads to radioactivity?

To achieve nuclear stability.

Why do radioactive isotopes emit radiation?

They have a proportionate number of protons and neutrons.

Why are nuclides on the line of stability stable?

Beta Particles

What type of radiation is most commonly emitted by nuclides above the line of stability?

Positrons and alpha particles

What type of radiation is commonly emitted by nuclides below the line of stability?

The region where nuclides have a stable neutron-to-proton ratio.

What does the line of stability represent?

parent nuclide

The nuclide before it undergoes radioactive decay.

daughter nuclide

the nuclide formed after the radioactive decay of the parent nuclide.

The parent transforms into the daughter through radioactive decay.

How are parent and daughter nuclides related?

Alpha Decay

A type of radioactive decay in which the nucleus emits an alpha particle.

Two protons and two neutrons (a helium nucleus).

What particles make up an alpha particle?

Radioactive nuclides with very high atomic numbers.

In what type of nuclides does alpha decay most commonly occur?

It is reduced by 2.

What happens to the atomic number during alpha decay?

It is reduced by 4.

What happens to the mass number during alpha decay?

beta minus (β⁻) decay

A type of radioactive decay involving the emission of a beta minus particle, also called a fast-moving energetic electron.

Negatron emission

What is another name for beta minus decay?

When a neutron transforms into a proton via the weak nuclear force, releasing a beta minus particle.

How is a beta minus particle produced in the nucleus?

Nuclides with an excessive number of neutrons or a high neutron-to-proton (n/p) ratio.

In what type of nuclide does beta minus decay occur?

By reducing the neutron excess through the emission of a negatron.

How does beta minus decay help the nucleus become stable?