Atomic structure
The structure of an Atom
 An atom is the smallest chemically distinct particle of an element, however, it does
consist of smaller units known as subatomic particles. Their number arrangement
in the atom determine the kind of elements, as well as their reaction in biological
and chemical processes.
 The three types of subatomic particles are protons, neutrons and electrons. Each
protons carries positive charge while the neutron has no electrical charge. These
two subatomic particles have almost the same mass and make up the dense central
part of an atom called the nucleus. Each electrons carries a negative electrical
charge that balances the positive charge on the protons. Unlike protons and
neutrons, electrons have a very small, negligible mass and are distributed around
the nucleus in orbitals, or electron shells.
 Neutrons has no electric charge but they add significantly to the mass of an
atom. In fact, the approximate atomic mass of an atom is the sum of the
mass of an atom of protons and neutrons added together.
 Though all atoms of a particular elements will always have the same number
of protons, sometimes the atoms of that element can have a different
number of neutrons. In this case, those atoms are called isotopes.
 All subatomic particles are present in the atoms of every elements but occur
in different number and proportion
● Instead of being arranged by relative atomic masses, elements could now be
arranged by atomic numbers without one elements out of order.
● The discovery of the nuclear charge also resulted in being able to determine
the number of electrons in an atom.
● It was previously known, that a neutral atom must have just enough
electrons to neutralize the positive nuclear charge and if an atom lost or
gained electrons it would become a charged atoms (ions). Therefore, in a
stable atom, the number of electrons must equal the number of protons.
Synthesis of New Elements
● During the formation of the universe, only the lightest elements were found hydrogen and helium along with trace amount of lithium and beryllium. As the
cloud of cosmic dust and gasses from the big bang cooled, stars formed, and
these then grouped together to form galaxies. Scientist have long been looking
for traces of unknown substances, But there came a point in the discovery when
scientists stopped looking for unknown substances and instead began
synthesizing new elements in laboratories.
● On the periodic table periodic table, there are 26 manmade elements that have
atomic numbers from 93 to 118. these elements are called transuranic elements.
● Transuranic elements are radioactive and can undergo nuclear fission.