Atomic Structure, Isotopes, and Radioactive Decay in Nuclear Chemistry

What is an atom?

The smallest unit of an element that retains its identity in a chemical reaction.

What are the three subatomic particles of an atom?

Protons, neutrons, and electrons.

What is the mass number of an atom?

The total number of protons and neutrons in an atom.

What does the atomic number represent?

The total number of protons in an atom.

What are isotopes?

Atoms of the same element that have equal protons but different numbers of neutrons.

What is the symbolic notation for silicon-28?

14/28 Si, where 28 is the mass number.

What is atomic mass?

The weighted average mass of all isotopes in a naturally occurring sample of the element.

What are stable isotopes?

Isotopes that are non-radioactive forms of atoms.

What are unstable isotopes?

Isotopes that emit ionizing radiation and are also called radioisotopes.

What is radioactive decay?

A spontaneous process of an unstable atom transitioning into a more stable form by emitting matter or energy.

What types of radiation are emitted during radioactive decay?

Alpha particles, beta particles, and gamma rays.

What happens during alpha decay?

An atom loses an alpha particle, lowering the atomic number by two and mass number by four.

What characterizes beta-minus decay?

A neutron becomes a proton and an electron is emitted, increasing the atomic number by one.

What occurs during beta-plus decay?

An unstable nucleus emits a positron, converting a proton into a neutron, decreasing the atomic number by one.

What is gamma decay?

The emission of gamma rays from a nucleus that is left in an excited state after alpha or beta decay.

What is the significance of the ratio of protons to neutrons in an atom?

An unstable ratio can lead to radioactivity; small nuclei typically have a ratio of 1:1, while large nuclei average 1:1.5.

Which elements have no stable isotopes?

Elements from Bismuth and above, as well as technetium and promethium.

What happens to heavy radioactive elements during decay?

They ultimately decay into lead, a stable element.

How many known stable isotopes exist?

There are 254 known stable isotopes.

What is the difference between stable and unstable isotopes?

Stable isotopes do not emit radiation, while unstable isotopes do and are radioactive.

What is a parent isotope?

An unstable isotope that transforms into a daughter isotope during radioactive decay.

What is a daughter isotope?

The product of a nuclear reaction that may be stable or unstable.

What is the process of radioactive decay?

It is a spontaneous transition of an unstable atom into a more stable form.

What is the charge of an alpha particle?

An alpha particle has a 2+ charge.

What happens to the atomic mass during beta decay?

The atomic mass remains unchanged during beta decay.

What does alpha radiation consist of?

Alpha particles (helium nuclei)

What is the charge of alpha particles?

2+

What is the penetrating power of alpha radiation?

Low (0.05 mm in body tissue)

What does beta radiation consist of?

Beta particles (electrons)

What is the charge of beta particles?

1-

What is the penetrating power of beta radiation?

Moderate (4 mm in body tissue)

What type of radiation consists of high-energy electromagnetic waves?

Gamma radiation

What is the charge of gamma radiation?

0

What is the penetrating power of gamma radiation?

Very high (penetrates body easily)

What happens to radioactive isotopes over time?

They decay into their daughter isotopes.

What is acute radiation syndrome?

Illness from very high levels of radiation exposure over a short period.

What are some health effects of ionizing radiation?

Skin burns, tissue damage, increased cancer risk.

What is the purpose of targeted alpha therapy?

To target and destroy cancer cells using alpha particles.

What is the half-life of a radioactive material?

The time it takes for half of the original sample to decay.

How does carbon dating work?

Living things take in carbon-14, which decays after death, allowing dating of fossils.

What is the half-life of cobalt-60?

5.27 years.

What is the main process used in stars to produce energy?

Nuclear fusion.

What is the effect of ionizing radiation on DNA?

It can cause structural damage directly or indirectly.

What are free radicals in the context of radiation exposure?

Reactive molecules that can damage DNA after radiation ionizes water.

What are some applications of radiation in medicine?

Diagnosing illnesses, treating diseases like cancer, sterilizing medical equipment.

What is the significance of isotopic signatures?

They are used to track and trace elements in the environment.

What is the result of beta decay?

An atom emits a beta particle and transforms into a different element.

What is the role of neutrons in nuclear fission?

They initiate a chain reaction by splitting large atoms.

What is the energy output of nuclear fusion compared to fission?

Fusion releases 3 to 4 times more energy than fission.

What is the effect of alpha particles if inhaled or ingested?

They can cause damage to internal tissues.

How do beta particles affect living tissue?

They can penetrate the skin and cause damage, but less than alpha particles.

What is the significance of Henri Becquerel's discovery?

It led to the study of radioactivity and the discovery of new radioactive elements.