G12 1S MT PhysSci: Nuclear Reactions

Atoms

are composed of a central nucleus surrounded by orbiting electrons.

Nucleus

consists of positively charged protons and neutral neutrons

3 Stages of Nucleosynthesis

1. The Big Bang

2. Stellar Formation

3. Stellar Explosion

Big Bang

Created the initial primordial, lightest elements—primarily H, He, and trace amounts of Li.

Stellar Formation

Gravity pulls H and He together to form stars. Inside these stars, extreme temperature and pressure drive nuclear fusion, forging elements from Be to Fe. Iron is the thermodynamic limit for normal stellar fusion.

Stellar Explosions

Elements heavier than Fe (eg., Gold, Platinum, and Uranium) require massive inputs of energy and are created during catastrophic cosmic events like supernovae and neutron star collisions.

Protons

- A positively charged subatomic particle.

- It is what determines the identity of an element

- Symbol of P

Neutrons

- A neutral subatomic particle

Symbol of N

- N=A-Z

Electrons

- A negatively charged subatomic particle.

- Symbol of E

Mass number/Atomic mass

- The sum of protons and neutrons

- Symbol of A

- A=Z+N

Atomic number

- Symbol of Z

- is used to also find the no. of protons

Isotope

An element of the same element/with the same number of protons but a different number of neutrons.

3 Types of Hydrogen

- Protium has 1 proton

- Deuterium has 1 proton and 1 neutron

- Tritium has a proton and 2 neutron.

Nuclear Fusion

- A type of nuclear reaction that makes use of combining two lighter nuclei to form a heavier nuclei.

- Generates less amount of nuclear waste

Nuclear Fission

- A type of nuclear reaction that refers to splitting of a heavy nucleus into a lighter nuclei

- Used in weapons and atomic bombs.

- Sustains power plants and nuclear weapons.

- Produce less radioactive products

Hydrogen (H)

The element with 1 proton and 1 neutron

Radioactive isotopes

Elements that are unstable and decays over a period of time.

Gamma rays

Strongest type of radiation

Transmutation

The process of changing one element to a different element by the decaying process.

Nuclear decay reaction/radioactive decay

- An unstable nucleus emits radiation and is transformed into the nucleus of one or more other elements.

- results to lower mass and energy

Nuclear transmutation reaction/nuclear transmutation

- A nucleus reacts with a subatomic particle or another nucleus to form a product nucleus that is **more massive** than the starting material.

Radioactivity

- A natural and spontaneous process by which the unstable atoms of an element emit or radiate excess energy in the form of particles or waves.

Ionising radiation

- The emitted particles or waves

- Has the ability to remove electrons from the atoms of any matter they interact with

Nucleosynthesis

- Formation of atomic nuclei

- It's how elements are made

- occurs when lighter elements combine (fusion) or when heavier elements break apart (fission & radioactive decay)

Helium (He)

- Symbol element for alpha particle.

- Has 2 protons and 2 neutrons