Chemical Bonding & Electron Energy Levels
Element – the most basic kind of matter; a substance that
cannot be broken down into simpler substances by ordinary
chemical means.
Atom – the smallest unit of an element that has all the
properties of the element; the basic building block of matter.
Proton – a particle of an atom that has a positive charge.
Neutron – a particle of an atom that has a neutral charge
or no charge.
Electron – a particle of an atom that has a negative charge.
Nucleus – the central core of an atom where the protons
and neutrons are located. The electrons are found just
outside the nucleus in the electron cloud.
Electron Cloud – the region just outside the nucleus where
electrons orbit; electrons have different amounts of energy.
The electrons nearest the nucleus have less energy than
electrons farther from the nucleus.
Chemical Bonds – the forces that hold atoms together.
Ion – an atom that has gained or lost one or more
electrons.
Reactivity – describes how likely an element is to form
bonds with other elements.
Ionic Bond – chemical bonds that are formed by the
transfer of electrons; the transfer of electrons of one
element’s outer energy level to another element’s outer
energy level. Ionic bonds seek to have a total of eight
electrons in their outer energy levels.
Covalent Bond – a chemical bond that is formed when two
atoms share electrons. Covalent bonds are most likely to
form between elements whose atoms have four, five, six or
seven valance electrons.
Inert – elements that are unable to react chemically.
Valance Electrons – electrons that are located in the
outermost energy level or energy shell of an element.
Atomic Energy Levels or Atomic Energy Shell – Areas
in the electron cloud where electrons are arranged by how
much energy the electrons have. The closer the electron is
to the nucleus, the more energy the electron has. When the
electron is further away from the nucleus it has less energy.
The valance electrons are furthest away which causes them
to bond with other elements.
Bohr Model – A model of electrons introduced and named
after scientist Niels Bohr in 1913. This model has an atom
consisting of a small, positively-charged nucleus orbited by
negatively-charged electrons.
Synthetic Elements – elements that are made by
scientists in a laboratory and do not exist in nature. Usually
elements with an atomic number of 92 or higher are
considered synthetic.