11. Variations of an atom that differ in the number of neutrons are called These variations can be stable or unstable. When a
variation of an atom has an unstable nucleus due to the number of neutrons, it is
called a
and emits an energy called
While this energy is dangerous to cells and their DNA,
it can also be used for various practical tasks in fields such as
and
12.
are small particles that have a negative charge and
orbit around the nucleus of an atom. They do not contribute to the atomic mass/
weight.
13. Electrons orbit around the nucleus of an atom in energy levels called
The first shell orbiting around the nucleus can hold a
maximum of
electrons. The second and third shells can hold a
maximum of
electrons. The outermost shell of an atom is
called its
shell and the electrons in that shell are called
electrons.
14. In a neutral atom (atom with no overall electrical charge), the number of
and
is equal.
15. If an atom's outside orbital is FILLED with electrons, that atom is said to be
and
_. Cite an example:
16. If an atom's outside orbital is NOT filled with electrons, that atom is said to be
and
_. All of the atoms found in living
organisms are in this category because chemical reactions are necessary for life.