What Are the Vertical Columns on the Periodic Table Called?
If you've ever glanced at a periodic table — whether in a classroom, a textbook, or that periodic table poster your chemistry teacher had framed — you probably noticed those vertical columns running from top to bottom. You know the ones. They look neat and organized, with elements stacked on top of each other like books on a shelf.
So what are those vertical columns actually called?
The vertical columns on the periodic table are called groups (sometimes referred to as families). So there are 18 groups in total, numbered 1 through 18 from left to right. Each group contains elements that share similar chemical properties because they have the same number of electrons in their outer shell.
That's the short answer. But here's the thing — there's a lot more to groups than just a name. Understanding what makes these columns special is actually the key to understanding why the periodic table works the way it does Small thing, real impact..
What Exactly Is a Group?
A group is a vertical column of elements in the periodic table. Each group contains elements arranged by their atomic number, but more importantly, they're organized so that elements within the same group behave similarly in chemical reactions The details matter here..
Here's why that matters: elements in the same group have the same number of valence electrons. Valence electrons are the electrons in the outermost shell of an atom — the ones that get involved in chemical bonding. When atoms interact with each other, it's these outer electrons that do the heavy lifting.
So when you see elements like lithium (Li), sodium (Na), and potassium (K) all sitting in the first column, it's not a coincidence. They all have one valence electron, which makes them behave in remarkably similar ways. They all form +1 ions, they all react vigorously with water, and they all belong to the alkali metal family And it works..
The Two Numbering Systems
Here's something that trips up a lot of people: there are actually two different numbering systems for the groups.
The older system uses Roman numerals and letters — IA, IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA. The "A" designation was used in the United States for many years Which is the point..
The modern system, recommended by the International Union of Pure and Applied Chemistry (IUPAC), uses simple numbers: 1 through 18. This is the system you'll see in most periodic tables today, and it's the one that avoids confusion.
Both systems refer to the same columns. Groups 13 through 18 correspond to IIIA through VIIIA. Also, group 1 is the same as Group IA. Group 2 is Group IIA. The noble gases, for example, sit in Group 18 (or VIIIA) The details matter here..
Groups vs. Periods
It's easy to confuse groups with periods, but they represent different things entirely The details matter here..
Groups are the vertical columns — the ones we're talking about in this article. They run from top to bottom.
Periods are the horizontal rows. Because of that, they run from left to right. There are 7 periods in the periodic table.
The key difference: elements in the same group share similar chemical properties. Elements in the same period have the same number of electron shells Still holds up..
So sodium (Na) in Group 1 behaves similarly to potassium (K) below it. But sodium in Period 3 behaves differently from beryllium (Be) in Period 2, even though they're both in Group 2.
Why Do Groups Matter?
Here's where this gets interesting. The group system isn't just a convenient way to organize elements — it's the entire reason the periodic table works Less friction, more output..
When Dmitri Mendeleev created the first periodic table in 1869, he arranged elements by atomic weight. But he noticed something strange: certain elements kept showing up in patterns. When he organized them by these patterns instead of just weight, the table started to make sense.
What he had discovered was that elements in the same group share chemical properties. In practice, this pattern was so reliable that he could use it to predict the properties of elements that hadn't been discovered yet. He left gaps in his table and predicted what elements would fill them — and he was remarkably accurate Still holds up..
The Main Group Elements
Groups 1, 2, and 13 through 18 are sometimes called the main group elements or representative elements. These are the elements in the "A" columns of older periodic tables That's the part that actually makes a difference..
- Group 1: Alkali metals (except hydrogen)
- Group 2: Alkaline earth metals
- Groups 13-18: Includes boron group, carbon group, nitrogen group, oxygen group, halogens (Group 17), and noble gases (Group 18)
These groups contain many of the most familiar elements — the ones you encounter in everyday life.
The Transition Metals and Inner Transition Metals
Groups 3 through 12 contain the transition metals. These are the elements in the middle block of the periodic table — the ones that fill in the gap between the left and right sides.
The transition metals include familiar elements like iron (Fe), copper (Cu), gold (Au), and silver (Ag). They tend to be hard, dense, and good conductors of heat and electricity Not complicated — just consistent..
Below the main table, you'll find the inner transition metals: the lanthanides (rows 6-7, typically shown separately) and actinides (rows 7-8). These technically belong to Groups 3 and 4, but they're usually displayed in their own rows for clarity Took long enough..
How Elements in the Same Group Behave
Let me give you a concrete example of why groups matter so much.
Consider the halogens: fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). They sit in Group 17 (or VIIA) Practical, not theoretical..
All of them:
- Have 7 valence electrons
- Form -1 ions when they gain an electron
- Exist as diatomic molecules (F₂, Cl₂, Br₂, I₂) under normal conditions
- React vigorously with alkali metals to form salts
- Are poisonous in their elemental form
Chlorine gas and iodine solid don't look much alike. But chemically, they're cousins. They behave the same way in reactions because they have the same number of valence electrons Took long enough..
This is the power of the group system. Once you understand how one element in a group behaves, you have a pretty good idea how all the others will behave Easy to understand, harder to ignore..
The Exception: Hydrogen
Hydrogen sits in Group 1, above the alkali metals. But it's not actually an alkali metal.
Hydrogen has just one electron, which puts it in Group 1. But it's a gas at room temperature, not a metal. Because of that, it doesn't behave like the alkali metals at all. Most periodic tables put hydrogen in Group 1 simply because that's where it belongs by electron configuration, even though its properties are unique.
At its core, one of those quirks that reminds you chemistry is about patterns — but nature doesn't always follow the rules perfectly It's one of those things that adds up. But it adds up..
Common Mistakes People Make
Confusing Groups with Families
Here's something that causes confusion: groups and families are the same thing. On top of that, when someone says "alkali metal family," they're talking about Group 1. When someone says "halogen family," they're talking about Group 17 Turns out it matters..
The terms are interchangeable. Some textbooks prefer "group," others prefer "family." It doesn't matter which one you use — just know they're talking about the same vertical columns Still holds up..
Forgetting There Are 18 Groups
Some people think there are only 8 groups (matching the old IA-VIIIA system). Others get confused because the transition metals sit in the middle and seem like a separate category.
But the modern periodic table has 18 groups. Because of that, the transition metals are simply Groups 3 through 12. They're still groups, just with different properties than the main group elements.
Ignoring the Group Number When Solving Problems
If you're studying chemistry, the group number tells you how many valence electrons an element has. For main group elements, this is straightforward: Group 1 = 1 valence electron, Group 2 = 2, Group 13 = 3, Group 14 = 4, Group 15 = 5, Group 16 = 6, Group 17 = 7, Group 18 = 8 (full shell) Simple, but easy to overlook..
This is incredibly useful for predicting how elements will bond. But it's easy to forget this relationship when you're focused on memorizing facts instead of understanding the pattern.
Practical Tips for Working with Groups
Learn the Group Names
Knowing the names of the groups makes chemistry much easier:
- Group 1: Alkali metals
- Group 2: Alkaline earth metals
- Group 17: Halogens
- Group 18: Noble gases
These four groups come up constantly. The transition metals (Groups 3-12) don't have catchy family names — they're just called transition metals It's one of those things that adds up..
Use the Group Number to Predict Valence Electrons
For main group elements (Groups 1, 2, 13-18), the group number directly tells you the number of valence electrons:
- Groups 1-2: group number = valence electrons
- Groups 13-18: group number - 10 = valence electrons
So Group 13 elements have 3 valence electrons. Group 16 elements have 6. This pattern holds for all the representative elements No workaround needed..
Remember the Periodic Law
The periodic law states that elements in the same group have similar properties. In real terms, when you're trying to predict how an element will behave, look at the other elements in its group. They'll give you a good idea of what to expect.
FAQ
What are the vertical columns on the periodic table called?
The vertical columns are called groups (or families). There are 18 groups in total, numbered 1 through 18 from left to right.
How many groups are on the periodic table?
There are 18 groups on the modern periodic table. Some older tables used a different numbering system with Roman numerals (IA through VIIIA), which effectively had 8 groups, but the 18-group system is the current standard.
What is the difference between a group and a period?
A group is a vertical column (top to bottom), while a period is a horizontal row (left to right). Elements in the same group have similar chemical properties. Elements in the same period have the same number of electron shells.
What are the elements in Group 1 called?
Group 1 elements (except hydrogen) are called alkali metals. They include lithium, sodium, potassium, rubidium, cesium, and francium. They're all highly reactive metals that form +1 ions Not complicated — just consistent..
What are the elements in Group 18 called?
Group 18 elements are called noble gases. They include helium, neon, argon, krypton, xenon, and radon. They have full outer electron shells, which makes them largely unreactive No workaround needed..
The vertical columns on the periodic table are called groups, and understanding them is the key to making sense of chemistry. Even so, once you know that elements in the same group behave similarly, you can predict chemical properties with just a glance at the table. That's the real power of the periodic table — not just memorizing facts, but seeing the patterns that make those facts inevitable.
This changes depending on context. Keep that in mind.
