Electrons
Electrons are the negatively charged particles of atoms. Together, all of the electrons of an atom create a negative charge that balances the positive charge of the protons in the atomic nucleus. Electrons are extremely small compared to all of the other parts of the atom. The mass of an electron is almost 1,000 times smaller than the mass of a proton.
Q: An electron has a mass that is much less than a proton.
A. True
B. False
A: True. Electrons are incredibly small compared to both protons and neutrons. Both neutrons and protons are over 1,000 times larger than an electron.
Electrons are found in clouds that surround the nucleus of an atom. Because electrons move so quickly, it is impossible to see where they are at a specific moment in time. After years of experimentation, scientists discovered specific areas where electrons are likely to be found. These shells change depending on how many electrons an element has. The higher the atomic number, the more shells and electrons an atom will have.
Q: Any electron can only be found in one of the seven possible atomic shells.
A. True
B. False
A: False. Electrons can be found in any of the atomic shells that surround the nucleus. Electrons fill the shells closest to the nucleus first. The innermost shell only holds two electrons. There is a probability that an electron will remain in one area. However, if energy is added to the atom, the electron can jump to different orbitals and spins.
BONDS
Electrons play a major role in many chemical bonds. There is one type of bonding called electrovalent bonding (ionic) where an ion from one atom is transferred to another atom. It is an even trade, creating two ions. The second type of bonding is called covalent bonding. Electrons are actually shared between two or more atoms in a cloud. Both types have specific advantages and weaknesses.
Follow the path of the shared electron in the diagram of a covalent bond at right.
Electrons are very important in the world of electronics. The very small particles stream through wires and circuits creating currents of electricity. The electrons move from negatively charged parts to positively charged ones. The negatively charged pieces of any circuit have extra electrons while the positively charged pieces want more electrons. The electrons then jump from one area to another. When the electrons move, the current can flow through the system.
In what directions do electrons move, or flow, in "electrical current"?
adapted from Rader's chem4kids.com