
Electrons
Electrons
are subatomic particles. They are negatively charged.
According to Niels Bohr's atomic model,
electrons go around / orbit the nucleus of an atom at discrete
energy levels or shells. The outer most shell of an atom is called
the valence shell and the electrons in this shell are known as the
valence electrons.
Atoms can form bonds by
o donating or accepting electrons (forming ionic bonds).
o sharing electrons (forming covalent bonds).
In metals, electrons form "clouds" which bond the atoms together.
This is known as the metallic bond.
If a potential difference is created between two parts / terminals
of a piece of metal, the electrons will flow. The flow of electrons
(which are charges) is referred to as the electric current.
See also the other subatomic particles: protons
and neutrons.
Elektron
Elektron merupakan zarah subatomik. Elektron bercas negatif.
Menurut model
atom
Niels Bohr, elektron-elektron mengorbit nukleus atom pada aras
tenaga atau petala-petala tertentu. Petala elektron yang terluar
(terjauh daripada nukleus) dikenali sebagai petala valens.
Elektron-elektron yang berada di petala ini dipanggil elektron
valens.
Atom-atom boleh mengikat secara
o menderma atau menerima elektron (membentuk ikatan
ionik)
o mengongsi elektron (membentuk ikatan kovalen).
Dalam logam, elektron-elektron membentuk "awan" yang mengikat
atom-atom bersama. Ikatan begini dikenali sebagai ikatan
logam.
Sekiranya perbezaan keupayaan diwujudkan di antara dua bahagian /
terminal sesuatu logam, elektron-eletron akan mengalir. Pengaliran
elektron-elektron (yang merupakan cas) juga dipanggil aliran
eletrik.
Baca juga zarah-zarah subatomik lain: proton dan
neutron.