Other Flashcards
What is the Formula for exponential decay?
A(t)=Aoe^-kt
What are the four types of decay?
Alpha Decay: where an alpha particle (2 protons & 2 neutrons) separate from a nucleus creating a new atom.
Beta Decay: Where a neutron becomes a proton by releasing a Beta particle (an electron) creating a new atom without changing the atomic mass
Positron Emission: Where a proton becomes a neutron by releasing a proton (basically a positive electron) creating a new atom without changing the atomic mass
Gamma Decay: Where the nucleus shifts creating a Gamma Ray (a high powered wave) that does not create a new atom or change the mass.
What forces are acting in the neucleus?
The electrostatic force: Repelling like charges
The strong force: Holding the nucleus together acting on all nucleons over a short distance.
The strong force is greater than the electrostatic force
The weak nuclear force: Allows an election to be given to stabilize the nucleus
When are nuclei stable?
In small nuclei (less than 20 protons (Z)) the nuclei is stable in a N/Z ratio equal to one.
In larger nuclei (more than 20 protons) the nuclei is stable in a N/Z ratio equal to 1.5. (because you NEED more neutrons)
In even larger nuclei (more than 83 protons) pretty much all nuclei are unstable and will undergo radioactive decay.
What do nuclei equations represent?
Only the nucleus’ of the atoms. Nucleons and charge a are conserved.
What are in nuclei eqations?
The symbol of the element, the atomic mass, and the atomic number. An electron (B) or positron when needed. Make sure that neutrons and charge are conserved.
What are the different types of chemical bonds?
Non-polar covalent bond: Bond between two nonmetals of similar electronegativity. (less than 0.5 electronegativity difference)
Polar covalent bond: Bond between two nonmetals of non-similar electronegativity. (greater than 0.5 electronegativity difference)
Ionic Bond: Bond between a metal and a metal or nonmetal or between two nonmetals with a great electronegativity difference (around 1.7 difference)
What is the geometry for each number of electron clouds?
5: trigonal bipyramidal or see saw (non bonded electrons)
3: trigonal planar or bent/angular (non bonded electrons)
2: Linear shape
How do you find formal charge?
Minus the number of shared electrons around the atom by the atoms’ original number of valence electrons to get zero (minimize).
What are the steps for molecular shape?
- Draw a dot structure to show the valence electrons.
- Count the number of “electron clouds” surrounding the central atoms
- Predict the geometry of the electron clouds around the central atom
- Ignore any lone pairs and predict the geometry of the molecule/ion
