Ineed one last question to finish up, ! besides the major types of radioactive decay there are two others: positron emission and electron capture. -compare and contrast positrons with electrons -explain how positron emission works and how it causes transmutations -explain how electron capture works and how ir causes transmutations -compare the transmutations caused by positron emissions and electron capture

Positron emission = emission of a positron and a neutrino when a proton is convert into a neutron. The total number of particles in the nucleus doesn't change, -1 proton +1 neutron

It's a spontaneous reaction for some nucleus.

eg:

Positron = e+

Neutrino=ve

O-15 --> N-15 + e+ +ve

Electron capture= A nucleus absorb an electron while a proton is convert in a neutron and emit a neutrino. The total number of particles in the nucleus doesn't change, -1 proton +1 neutron

eg:

Al-26 +e- --> Mg-26 + ve

Electron capture and positron emission are two mechanisms to explain the decay of some unstable isotopes. Electron capture is usually observed when the energy difference between the initial and final state is low. Mainly because of the larger amount of kinetic energy need for the expulsion of two particles with the positron emission mechanism.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.

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