Nuclear chemistry Flashcards
This is a branch of chemistry that is concerned with the study of the nucleus
What is an nucleus made up of?
Protons
nutrons
What is an Isotope?
An isotope is an element that have the same number of protons ( protons never changes) but that have different number of neutons.
This changes the element’s atomic mass.
What is the mass number made up of? or atomic mass or relative isotopic mass?
Made up of protons and nutrons
What is the charge of a
Electron
Neutron
Protons
- Electron: -1.602 X 10 ^ -19
- Neutron: 0
- Protons: 1.602 X 10 ^19
what is the relative isotopic mass? And how is it measured ?
- a unit of comparison that compares the atomic mass of elements to carbon 12 atoms which has a mass of 12
- relative isotopic mass is also related to the atomic mass unit: 1 atomic mass unit or AMU = 1/12 (mass of carbon 12 atom)
How do we know if an atoms is stable or unstable? How can we tell what type of decay will occur
- If it is an isotope
- If too many neutrons: beta - decay
- too many protons : beta + decay
- Too many many protons ( more than 82): alpha decay
What are the two nuclear forces that are present in the atoms?
- Strong force:the force that bonds protons and nutrons
- Electromagnetic force: force that are created by the repulsion of positive harges
- However the nucleus is able to stay bond together because the strong forces is greatest than electromagnetic forves.
What is radioactive decay?
Unstable nuclei emit radiation in order to stabilize itself
What determines if the atom is stable? And what can make a nucleus unstable?
- The strong force determines how stable and atom is because it holds enough energy to keep the nuclei together ( protons and neutrons)
- if they have to many protons or too many neutrons for instance an isotope, these upset the strong forces.
How does an unstable nuclei tries to balance itself?
It does so by giving off either a proton or neutrons to make sure the strong force is holding the nucleus together, that is what creates radio active decay
What are the three types of decay?
- alpha decay
- Beta decay -
- Beta decay +
What is Alpha decay? what is an alpha particle made up off?
What is their mass and charge and what happens when an atoms looses and alpha particle?
- the loss of an alpha particle
- An alpha particle is made of two protons and two neutrons
- each alpha particle have a mass of 4 and a charge of +2
When it looses an alpha particle
- When an atom looses an alpha particle it looses a mass of 4 ( so their atomic number decrease by 4) and the atomic number ( the protons) decreases by 2
- Results: a new element is form that is two places lower in the periodic table of the element that loss the protons and neutrons.
what is beta negative decay?
- When an atom has too many neutron it can experience beta decay
- two protons and one neutrons leave
- however the neutrons changes itself into a protons and an electon
- The proton stays with the atom but the electon is lost
- when you loose electron it is at a high energy ( has the potential of getting closer to a proton)
Results of Beta decay
- As your atom gains a proton however it will increase the atomic mass of the particle ( which is made of protons) so the resulting element will have one place higher in the periodic table then the atoms that emitted the decay.
What is beta positive decay?
- When an atom has too much protons it goes through beta positive decay
- A proton is converted into a neutron and a positive beta particle called a positron
What are positrons?
- positrons have the same mass as an electron but have a positive charge
Results
- By loosing a protons but gaining a neutron the atomic mass increases by one but the atomic number decreses by 1
What is nuclear half-life
- How long it takes for the nuclear processes (number of protons and neutrons) change, to go through decay or
- the time that it takes for 1/2 of a substance to decay
