24 Apr Unveiling the Secrets of the Periodic Table: 3 Cool Trends You Should Know
Unveiling Secrets of the Periodic Table : 3 Cool Trends You Should Know
The periodic table isn’t just a chart of elements; it’s a treasure map of information and trends that reveal the hidden order of the universe.
This is why the Periodic Table is a compulsory chapter in both the Secondary/IP Chemistry and JC Chemistry syllabus.
Let’s explore three major trends in the periodic table—with some fun facts to spice it up!
1. Shrinking from left to right
What’s the Trend:
As you move across a Period, from left to right, atoms appears smaller even though their relative atomic mass are higher.
But Why:
First, atomic radius is measured from the center of the nucleus to the valence electron shell.
Now, imagine a tug-of-war. The electrons, which are negatively charged, repels each other as its added to the same electron shell. The nucleus, on the other hand, contains protons that attract the electrons and pull them closer.
Across the Period, electrons are added to the same electron shell while the number of protons increases. The nucleus is the stronger “puller” in this case, dragging the electrons inward as its “strength” grows.
Fun Fact:
An atom of sodium has a radius almost twice as big as an atom of chlorine even though chlorine has a higher relative atomic mass!
2. Ionization Energy: The “Break-Up” Resistance
What’s the Trend:
The first ionization energy increases as you move across a Period from left to right and decreases as you move down a Group. This is the energy needed to “break up” a gaseous atom by removing its outermost electron to form a singly positively charged gaseous ion.
But Why:
Across the Period, electrons are added to the same electron shell while the number of protons increases. The nucleus is the stronger “puller” in this case, dragging the electrons inward as its “strength” grows.
However, as we go down the Group, electron are added to additional electron shells. Even though the number of protons increases in elements down the Group and the nucleus “strength” does not grow enough to pull the electrons inwards as the electrons gets further away from the nucleus.
Talk about a fragile, long distance, relationship…
Fun Fact:
Francium (Fr), an alkali metal, is an atom with one of the largest atomic radius. Its valence electrons are so easily lost that Francium is so unstable and so rare you could never hold it! If you get hold of Francium, half of it would have decayed in 22 minutes!
3. Electronegativity: The Popularity Contest
What’s the Trend:
Electronegativity increases across a period and decreases down a group. This measures an atom’s ability to attract electrons in a chemical bond.
But Why:
Think of it as a game of magnetism. The closer the electron is to the nucleus and the higher the “strength” of the nucleus, the better an element can attract electrons.
Fluorine (F) is like the ultimate electron magnet, while cesium (Cs) barely tries.
Fun Fact:
This explains why fluorine is so reactive—it’s constantly trying to grab electrons from other elements hence fluorine is capable of reacting with almost every element, even certain noble gases like xenon.
At PMC, we believe in making chemistry, physics, and math not just understandable but exciting.
Our Secondary/IP Chemistry & JC H2 Chemistry classes don’t just prepare students for exams—they ignite curiosity and passion for science. Whether it’s uncovering the secrets of the periodic table, mastering challenging formulas, or solving complex problems with confidence, we’re here to guide students every step of the way.
Join us to experience the difference in learning—where understanding meets inspiration, and results follow naturally.
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