periodic table

Question 1

periods

Answer 1

There are 7 periods (horizontal rows) in the Periodic Table.

The period number indicates the number of electron shells in the elements of that period.

For example, elements in Period 1 have 1 electron shell, elements in Period 2 have 2 electron shells, and so on.
As you move across a period from left to right, elements typically change from metals to nonmetals.

Question 2

groups

Answer 2

There are 18 groups (vertical columns) in the Periodic Table.
Elements in the same group have similar chemical properties because they have the same number of valence electrons (electrons in the outermost shell).
Groups are often numbered 1 to 18, but sometimes they are also referred to by names based on their properties:
Group 1: Alkali metals (e.g., lithium, sodium)
Group 2: Alkaline earth metals (e.g., magnesium, calcium)
Group 17: Halogens (e.g., fluorine, chlorine)
Group 18: Noble gases (e.g., helium, neon)