How many groups and period are there in Periodic Table?

Question

Accepted Answer

The correct option is (3):

The Periodic Table is a fundamental organizational tool in chemistry, arranging all known elements based on their atomic number, electron configuration, and recurring chemical properties. This arrangement helps us predict an element's behavior and reactivity. The table is structured into horizontal rows called periods and vertical columns called groups. There are precisely 7 periods in the modern periodic table. Each period represents the principal energy level or shell in which electrons are found, with the number of the period indicating the highest occupied electron shell. As for groups, there are 18 vertical columns. Elements within the same group share similar chemical properties because they have the same number of valence electrons. Therefore, the correct count for groups and periods in the periodic table is 18 groups and 7 periods, making option 3 the accurate choice.

The incorrect option is (1): 7,7. This option incorrectly states that there are 7 groups. While there are 7 periods, the number of groups is significantly higher, reflecting the broader range of distinct chemical families.

The incorrect option is (2): 7,18. This option reverses the correct order. The first number typically refers to groups, and the second to periods. Stating 7 groups and 18 periods is incorrect, as there are 18 groups and 7 periods.

The incorrect option is (4): 18, 18. This option incorrectly states that there are 18 periods. The periodic table has only 7 periods, corresponding to the seven principal energy levels.