The IUPAC is an organization that regulates the physical laws of chemistry.

Democritus stated that atoms have different sizes, are never in motion and are separated by empty space.

In around the 17th century, alchemists explored the nature of matter intensely. They searched for exclusive prizes such as the alchemy of life.

Bohr Rutherford diagrams look as follows.

Valence electron are electron on the second outermost shell.

All atoms are in the search of a full octet to some extent.

Noble gases are highly reactive as they constantly search to fill their octet.

Anions and Cations come together to form a molecular compound.

Polyatomic ions are ions that consist of more than one atom.

99% of the human body is made of only 6 elements (oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus).

Isotopes are atoms of the same element that have different numbers of protons.

Isotopic abundance is the percentage of an isotope in a sample of an element.

Radioactive isotopes are isotopes that decay to form nuclear radiation.

The periodic table contains almost all of the known elements.

Hydrogen does not belong to a specific group of elements as it is an exception.

Transition metals are the metals that are found near the center of the periodic table. They are strong , hard metals with high melting points as well as good conductors of electricity. Many react with oxygen to form oxides. Some are multivalent.

Metalloids are found along the staircase.

Noble gases are gases at room temperature with high melting and boiling points. They are extremely unreactive.

Halogens may be solid liquid or gas at room temperatures and are extremely reactive. They also exhibit non-metallic properties such as no lustre and non-conduction.