Periodic Table · 6 min read
Arrangement of the periodic table
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Introduction to the periodic table
Think of the periodic table as a shelf in a big supermarket. Just as a shopkeeper puts all the soaps in one row and all the milk in another, scientists use the periodic table to arrange every chemical element found on Earth so they are easy to study.
The periodic table is a display of all known chemical elements arranged according to their atomic numbers, such that elements with similar chemical properties fall into the same column.
The modern periodic table is the master map for all chemists, showing how every atom is related to the next.
The horizontal rows or periods
The rows that go from left to right like the way you write in your notebook are called Periods. There are seven periods in total.
As you move across a period, you are adding one proton and one electron to the atom at each step.
The vertical columns or groups
The columns that go from top to bottom like a borehole pipe are called Groups. Elements in the same group are like siblings; they behave very much alike because they have the same number of electrons in their outermost shell.
Elements in the same group have similar chemical properties, just like members of the same family might have the same eye color.
The Periodic Law
Long ago, scientists tried arranging elements by weight, but it didn't quite work. Today, we follow a specific law based on the Atomic Number (the number of protons in the atom).
The Periodic Law states that the properties of the elements are a periodic function of their atomic numbers.
This means if you arrange elements by their atomic numbers, their character and behavior will repeat at regular intervals.
Blocks of elements
The table is also divided into four big blocks named after the sub-shells where the last electron lives: s-block, p-block, d-block, and f-block.
1. s-block: Groups 1 and 2 (the left side).
2. p-block: Groups 13 to 18 (the right side).
3. d-block: The transition metals in the middle.
4. f-block: The two rows usually pulled out at the very bottom.
Key points
- •Elements are arranged by increasing atomic number.
- •Horizontal rows are called periods.
- •Vertical columns are called groups.
- •Elements in a group share similar chemical properties.
- •The table is divided into s, p, d, and f blocks.