Electrons

Question	Answer
Electrons are the lightest of all the sub-atomic particles	They weigh 1/1836 of the weight of a proton
The radius of an electron is < \(10^-15\) m	It's impossible to see them with the naked eye!
Electrons are negatively charged, and have the symbol \(e^-\)	They have a charge of \(-1.602×10^-19\) Coulomb - The standard unit of charge
The charge of the electron was measured by Robert Millikan with his oil-drop experiment	When they performed the experiment in 1909, they only had an error margin of 0.3%!
Unlike the protons and neutrons, the electrons orbit the nucleus	They travel at very high speeds
In 1913, the scientist Niels Bohr proposed that the electrons were in orbits of different energy levels	They can move between levels, but only if the emit or absorb a photon of a certain frequency
The electrons enable atom to form chemical bonds	A covalent bond is when atoms share a pair of electrons
An ionic bond is when two charged atoms are attracted towards each other	A positively charged atom is a cation, and a negatively charged atom is an anion

Resource summary

	Created by leonie.examtime over 10 years ago

	Copied by ed.wilson89 over 10 years ago