Vertical Columns On The Periodic Table Are Called

The Answer Seems Simple, Until You Think About It

You've seen the periodic table a hundred times. Which means those neat rows and columns look like they were laid out by a designer who really loved spreadsheets. And if someone asked you what the vertical columns are called, you'd probably say "groups" without hesitation.

But here's the thing — that's only part of the story. And the full story is actually more interesting than you might expect.

Because while "groups" is the standard term, it wasn't always that way. And the way we label those columns today reflects a lot about how science communicates, evolves, and sometimes stumbles through its own history.

## What Is a Group on the Periodic Table

A group is a vertical column of elements on the periodic table. Plus, that's the straightforward part. These columns contain elements that share remarkably similar chemical properties because they all have the same number of electrons in their outermost shell.

Think about it this way: if elements were people with personalities, the elements in the same group would be like siblings. They might look different — some tall, some short, some shiny, some dull — but they'd behave in fundamentally similar ways.

The noble gases in group 18 are the most extreme example. Whether it's helium (light enough to make your voice sound like a cartoon character) or radon (a dense, radioactive gas), they all share that same unwillingness to react with just about anything. It's their electron configuration that makes them so aloof.

## Why Groups Matter More Than You Think

Here's what most people miss: the concept of chemical periodicity — the repeating patterns in properties as you move across the table — is one of the most powerful ideas in all of chemistry. And groups are where that pattern shows itself most clearly.

When a chemist needs to predict how an element will behave, they don't memorize properties for hundreds of individual elements. A halogen in group 17 will form salts with metals. A transition metal in groups 3 through 12? Instead, they look at which group it belongs to. So an alkali metal in group 1 will react violently with water. Now you're getting into more complex territory, but you still have a starting point.

This isn't just academic. Groups are why your phone battery works, why your car's catalytic converter cleans up exhaust, and why the stain remover on your laundry room shelf can tackle organic compounds that water alone can't touch.

## How Group Numbering Actually Works (And Where It Gets Confusing)

The Modern IUPAC System

Today, groups are numbered from 1 to 18, left to right. Consider this: this seems logical enough. But there's a catch that catches people off guard.

Groups 1 and 2 are the alkali metals and alkaline earth metals. On the flip side, groups 13 through 18 cover the rest of the main-group elements. Still, straightforward. But then there's the transition metal situation.

Groups 3 through 12 are all transition metals. And here's where it gets genuinely confusing: the lanthanides and actinides — those two rows sitting below the main table — are actually part of groups 3 through 12. They're just pulled out to make the table fit on a page without looking like a mess.

The Old System You Might Still See

If you learned chemistry before the 1980s or so, you might remember the old American system. Here's the thing — instead of 1 through 18, groups were labeled with Roman numerals and superscripts like IA, IIA, IB, IIB, and so on. The main-group elements had A suffixes, the transition metals had B suffixes.

The problem? American textbooks used one scheme, European ones used another. Different countries used different systems. It was a mess that made international collaboration harder than it needed to be.

The International Union of Pure and Applied Chemistry (IUPAC) stepped in and standardized everything. But old habits die hard. Even today, you'll find older textbooks and some specialized fields still using the Roman numeral system.

The Rare Earth Complication

Here's a detail that genuinely frustrates chemistry educators: the placement of lanthanum and actinium. Are they part of the f-block, or are they d-block elements that happen to sit at the beginning of the lanthanide and actinide series?

Different periodic tables handle this differently. Others put them at the start of the f-block. Some put lanthanum and actinium in group 3 with scandium and yttrium. The IUPAC hasn't definitively settled this, which means you'll see both arrangements in textbooks and on classroom walls.

## Common Mistakes People Make About Groups

Confusing Groups with Periods

This happens constantly. On the flip side, groups are vertical columns. That's why periods are horizontal rows. But people mix them up all the time, probably because both words start with the same sound and both relate to organization.

The difference matters because elements in the same period have the same number of electron shells, while elements in the same group have the same number of valence electrons. These are completely different concepts.

Thinking All Groups Are Created Equal

The main-group elements (groups 1, 2, and 13 through 18) follow relatively predictable patterns. The transition metals (groups 3 through 12) are a different beast entirely. Their electron configurations are more complex, their chemistry more varied. The details matter here.

Continue exploring with our guides on how many seconds are in 6 hours and how many days in two years.

And then there are the lanthanides and actinides, which don't even get their own dedicated columns in most periodic tables. They're shoved off to the side like they're embarrassing relatives at a family reunion.

Assuming Group Number Equals Number of Electrons

This one trips up beginning chemistry students regularly. Here's the thing — yes, for the main-group elements, the group number often corresponds to the number of valence electrons. Group 1 elements have one valence electron. Group 17 elements have seven.

But this breaks down completely with the transition metals. Think about it: iron is in group 8, but it doesn't have eight valence electrons. Copper is in group 11, but it has an electron configuration that looks nothing like what you'd expect from its group number.

## Practical Tips for Working With Groups

Use Group Patterns to Predict Behavior

When you're trying to understand an unfamiliar element, start with its group. So if it's in group 1, expect high reactivity, especially with water. If it's in group 17, expect it to be a strong oxidizing agent. If it's in group 18, expect it to be inert.

This isn't foolproof — transition metals break almost every rule — but it's a solid starting point for the main-group elements.

Learn the Special Cases

Some groups have nicknames that are worth memorizing because they tell you something important about the elements' behavior:

• Group 1: Alkali metals (highly reactive, soft, low melting points)
• Group 2: Alkaline earth metals (reactive, but less so than alkali metals)
• Group 15: pnictogens (nitrogen, phosphorus, and their more exotic cousins)
• Group 16: chalcogens (oxygen and its relatives)
• Group 17: halogens (reactive nonmetals that form salts)
• Group 18: noble gases (inert gases that barely react)

These aren't just labels — they're clues about what kind of chemistry you're dealing with.

Pay Attention to Oxidation States

Elements in the same group tend to form similar ions. Group 17 elements typically form -1 ions. Group 1 elements almost always form +1 ions. Group 2 elements form +2 ions.

This is incredibly useful when you're balancing chemical equations or predicting the products of reactions. It's also why chemists can look at an unfamiliar compound and immediately have a sense of what it might do.

## FAQ

What are the vertical columns on the periodic table called?

The vertical columns are called groups. Each group contains elements that share similar chemical properties due to having the same number of valence electrons.

How many groups are there on the periodic table?

There are 18 groups in the modern periodic table, numbered from left to right as groups 1 through 18 according to the IUPAC system.

What's the difference between groups and periods?

Groups are vertical columns, while periods are horizontal rows. Elements in the same group have similar chemical properties, while elements in the same

The rows of the chart are called periods; each period corresponds to the filling of a new principal energy level, so moving from left to right the atomic number increases while the number of occupied shells stays constant within that row.

Transition‑metal elements, which occupy the d‑block, illustrate why the simple “group‑number‑equals‑valence‑electron‑count” rule often fails. But iron, for instance, can exhibit +2 or +3 oxidation states, and copper commonly forms +1 or +2 ions, reflecting the flexibility of the d‑subshell. Their chemistry is governed more by the number of electrons in the (n‑1)d and ns orbitals than by a fixed count of valence electrons.

The f‑block, containing the lanthanides and actinides, adds another layer of complexity. These elements involve the progressive filling of the 4f and 5f subshells, respectively, and their properties are shaped by the subtle interplay of shielding and relativistic effects. Although they are usually placed below the main body of the table, they are integral to understanding the overall trends in atomic size, magnetic behavior, and oxidation state diversity.

Modern IUPAC numbering (1‑18) eliminates the older Roman‑numeral system that could be ambiguous for the newer p‑block elements, making it easier to locate an element and infer its general behavior. Nonetheless, the most reliable way to anticipate an element’s chemistry is to combine group trends with a view of its electron configuration, especially for the transition and inner‑transition series.

Boiling it down, the periodic table’s groups provide a powerful framework for predicting the chemical character of main‑group elements, while the d‑ and f‑block elements remind us that nature often defies simple classifications. By viewing the table as a dynamic map rather than a rigid set of rules, students and practitioners can figure out the vast landscape of chemical reactivity with confidence.