Periods in Periodic Table

A period is a row of elements in the periodic table that have the same number of electron shells.
There are seven periods in the periodic table, labelled 1 to 7.

Period 1 (Shortest Period):

Contains only two elements, hydrogen, and helium.
Elements in this period have only one shell, called the K shell.

Period 2 (Short Period):

Contains eight elements, starting with lithium and ending with neon.
Elements in this period have two shells, the K and L shells.
The first two elements are metals, followed by metalloids and nonmetals.
The last six elements are all noble gases.

Period 3 (Short Period):

Contains eight elements, starting with sodium and ending with argon.
Elements in this period have three shells, the K, L, and M shells.
The first two elements are metals, followed by metalloids and nonmetals.
The last six elements are all nonmetals, except argon, which is a noble gas.

Period 4 (Long Period):

Contains 18 elements, starting with potassium and ending with krypton.
Elements in this period have four shells, the K, L, M, and N shells.
The first three elements are metals, followed by metalloids and nonmetals.
The last six elements are all noble gases.

Period 5 (Long Period):

Contains 18 elements, starting with rubidium and ending with xenon.
Elements in this period have five shells, the K, L, M, N, and O shells.
The first three elements are metals, followed by metalloids and nonmetals.
The last six elements are all noble gases.

Period 6 (Longest Period):

Contains 32 elements, starting with cesium and ending with radon.
Elements in this period have six shells, the K, L, M, N, O, and P shells.
The first two elements are metals, followed by metalloids and nonmetals.
The last six elements are all noble gases.

Period 7 (Incomplete Period):

Contains 32 elements, starting with francium and ending with oganesson.
Elements in this period have seven shells, the K, L, M, N, O, P, and Q shells.
The first element is a metal, followed by metalloids and nonmetals.
The last six elements are all synthetic, except for the last one, oganesson,

Groups in Periodic Table:

A group is a column of elements in the periodic table that share similar chemical and physical properties. There are 18 groups in the periodic table, labelled 1 to 18.

Group I – Alkali Metals:

Contains elements such as lithium, sodium, and potassium.
These elements are highly reactive and have one valence electron.
They are soft, low-melting-point metals that react violently with water.
They are often used in batteries, soaps, and fertilisers.

Group II – Alkaline Earth Metals:

Contains elements such as magnesium, calcium, and barium.
These elements are also highly reactive but less so than alkali metals.
They have two valence electrons and are harder and denser than alkali metals.
They are often used in construction materials, medical applications, and fireworks.

Group III – Boron Family:

Contains elements such as boron, aluminium, and gallium.
These elements have three valence electrons and are commonly found in minerals and ores.
They have a wide range of uses, including in alloys, ceramics, and electronics.

Group IV – Carbon Family:

Contains elements such as carbon, silicon, and lead.
These elements have four valence electrons and are important for their ability to form covalent bonds.
They are commonly used in electronics, semiconductors, and batteries.

Group V – Nitrogen Family:

Contains elements such as nitrogen, phosphorus, and arsenic.
These elements have five valence electrons and are important for their role in the nitrogen cycle and DNA structure.
They are commonly used in fertilisers, explosives, and semiconductors.

Group VI – Oxygen:

Contains elements such as oxygen, sulphur, and selenium.
These elements have six valence electrons and are important for their role in organic molecules and respiration.
They are commonly used in pharmaceuticals, pigments, and rubber production.

Group VII – Halogens:

Contains elements such as fluorine, chlorine, and iodine.
These elements have seven valence electrons and are highly reactive nonmetals.
They are commonly used in disinfectants, plastics, and dyes.

Group VIII – Noble Gases:

Contains elements such as helium, neon, and argon.
These elements have a full outer shell of electrons and are chemically inert.
They are commonly used in lighting, welding, and cryogenics.

Group IB to VIII B (Transition Elements):

These Groups are metals.
In chemical reactions they show Variable valencies.
Their valence shells are incomplete.