The Periodic Table is organized into rows, columns, and blocks, each reflecting specific properties of the elements. Let’s break it down:

a. Periods (Rows)

• The horizontal rows of the Periodic Table are called periods.
• Each period corresponds to the number of electron shells in an atom. For example, elements in the first period have one electron shell, while elements in the second period have two.
• As you move from left to right across a period, the atomic number increases by one for each element. This means each element has one more proton and one more electron than the element preceding it.
• A pattern in chemical properties emerges across a period. For instance, elements on the left side of a period (like metals) tend to lose electrons, while those on the right (non-metals) tend to gain electrons.

b. Groups (Columns)

• The vertical columns are known as groups or families.
• Elements in the same group have similar chemical properties because they have the same number of valence electrons (electrons in the outermost shell). These electrons determine how an element will react chemically.
• There are 18 groups in the modern Periodic Table. Each group is labeled either by numbers (1 to 18) or, in some older versions, with a combination of numbers and letters (e.g., 1A, 2A, etc.).

Some key groups include:

• Group 1: Alkali Metals (e.g., lithium, sodium, potassium) – These are highly reactive metals with one valence electron.
• Group 2: Alkaline Earth Metals (e.g., magnesium, calcium) – These metals have two valence electrons and are less reactive than alkali metals.
• Group 17: Halogens (e.g., fluorine, chlorine) – Highly reactive non-metals that gain electrons easily.
• Group 18: Noble Gases (e.g., helium, neon) – These gases are chemically inert because they have a full set of valence electrons, making them very stable.

c. Blocks

The Periodic Table is divided into four blocks based on the type of atomic orbital where the valence electrons are found. These blocks are:

• s-block: Groups 1 and 2 (and hydrogen and helium). Elements in this block have their outermost electrons in an s orbital.
• p-block: Groups 13 to 18. These elements have their outermost electrons in a p orbital.
• d-block: Transition metals in the middle of the table (Groups 3 to 12). Their valence electrons are found in d orbitals.
• f-block: These are the lanthanides and actinides, which are often displayed separately at the bottom of the table. Their electrons occupy f orbitals.

d. Metals, Non-Metals, and Metalloids

• The Periodic Table is also visually divided between metals, non-metals, and metalloids.
• Metals are found on the left side and center of the table. They are typically good conductors of heat and electricity, malleable, and shiny.
• Non-metals are on the right side of the table and have opposite properties: they are poor conductors, brittle in solid form, and lack luster.
• Metalloids, which sit along the staircase-like line between metals and non-metals, have properties of both and are used in semiconductors and other technologies.