Difference Wiki

Period vs. Group: What's the Difference?

Edited by Huma Saeed || By Sawaira Riaz || Published on February 12, 2024
In the context of the periodic table, a period refers to a horizontal row of elements, while a group refers to a vertical column, each categorizing elements with shared properties.

Key Differences

In the periodic table, a period represents a horizontal row. Elements in the same period have the same number of atomic orbitals. Each period indicates the highest energy level an electron in that element occupies in its ground state. A group, however, is a vertical column in the periodic table. Elements within the same group share similar chemical properties due to having the same number of electrons in their outermost shell.
Sawaira Riaz
Feb 12, 2024
The length of each period varies because it reflects the number of elements that can occupy the available sublevels. There are seven periods in the periodic table. In contrast, groups are consistent in the periodic table, with 18 groups in total, including both the main group elements and the transition metals.
Sawaira Riaz
Feb 12, 2024
Elements in the same period are not as chemically similar as those in the same group. This is because their valence electrons are in different shells. In groups, elements tend to exhibit similar chemical and physical properties, as they have similar valence electron configurations.
Sawaira Riaz
Feb 12, 2024
The concept of periodicity, which refers to the recurring trends in the properties of elements across each period, is fundamental in chemistry. Group trends are also crucial, as elements in a group often react similarly or have related physical properties.
Aimie Carlson
Feb 12, 2024
Periods in the periodic table illustrate the progressive filling of electron shells, which influences an element's reactivity and properties. In groups, the elements typically have a similar state of matter at room temperature, similar reaction behaviors, and trends in physical properties like melting and boiling points.
Sawaira Riaz
Feb 12, 2024
ADVERTISEMENT

Comparison Chart

Orientation

Horizontal row in the periodic table
Vertical column in the periodic table
Sawaira Riaz
Feb 12, 2024

Element Properties

Same number of atomic orbitals
Similar chemical properties
Huma Saeed
Feb 12, 2024

Length/Consistency

Varies in length
Consistent, with 18 groups
Sawaira Riaz
Feb 12, 2024

Chemical Similarity

Less chemically similar
More chemically similar
Sawaira Riaz
Feb 12, 2024

Trends

Illustrates filling of electron shells
Exhibits similar reactivity and state
Sawaira Riaz
Feb 12, 2024
ADVERTISEMENT

Period and Group Definitions

Period

A set of elements with the same number of atomic orbitals.
All elements in the second period have electrons in two shells.
Sawaira Riaz
Jan 18, 2024

Group

Indicates consistent trends in properties.
Elements in a group often have similar melting points.
Janet White
Jan 18, 2024

Period

A division based on electron shells.
Moving across a period, elements progressively fill up their outer electron shells.
Sawaira Riaz
Jan 18, 2024

Group

A vertical column in the periodic table.
Group 1 contains the alkali metals.
Sawaira Riaz
Jan 18, 2024

Period

A horizontal row in the periodic table.
Oxygen and fluorine are in the same period.
Sawaira Riaz
Jan 18, 2024

Group

Elements with similar chemical properties.
Elements in a group typically react in similar ways.
Sawaira Riaz
Jan 18, 2024

Period

Reflects the highest energy level of electrons in the ground state.
Elements in the third period have electrons in the third shell.
Harlon Moss
Jan 18, 2024

Group

Characterized by the same number of valence electrons.
All elements in Group 17 have seven valence electrons.
Huma Saeed
Jan 18, 2024

Period

Indicates progressive filling of electron shells.
The periodic table's periods help us understand electron configuration.
Aimie Carlson
Jan 18, 2024

Group

Shares similar reactivity and state of matter.
Group 18 elements are all noble gases and share similar non-reactive properties.
Aimie Carlson
Jan 18, 2024

Period

An interval of time characterized by the occurrence of a certain condition, event, or phenomenon
A period of economic prosperity.
Sawaira Riaz
Jan 17, 2024

Group

An assemblage of persons or objects gathered or located together; an aggregation
A group of dinner guests.
A group of buildings near the road.
Sawaira Riaz
Jan 17, 2024

FAQs

What does a period indicate about an element?

It indicates the highest energy level an electron occupies in its ground state.
Sawaira Riaz
Feb 12, 2024

Are periods consistent in length?

No, the length of periods varies.
Aimie Carlson
Feb 12, 2024

Do elements in the same group have similar reactivity?

Yes, they typically share similar chemical behaviors.
Sawaira Riaz
Feb 12, 2024

Do elements in the same period have similar properties?

They have similar energy levels, but not necessarily similar properties.
Sawaira Riaz
Feb 12, 2024

How many groups are there in the periodic table?

There are 18 groups.
Aimie Carlson
Feb 12, 2024

How many periods are in the periodic table?

There are seven periods.
Huma Saeed
Feb 12, 2024

Do elements in the same period have the same number of electrons?

They have electrons in the same shell, but not the same number.
Janet White
Feb 12, 2024

What is a period in the periodic table?

A horizontal row of elements with the same number of atomic orbitals.
Sawaira Riaz
Feb 12, 2024

What do groups tell us about elements?

They indicate similar valence electron configurations and chemical properties.
Harlon Moss
Feb 12, 2024

Are all elements in a group in the same state of matter?

Often they are, but not always.
Sawaira Riaz
Feb 12, 2024

What's an example of a group trend?

Alkali metals becoming more reactive down the group.
Sawaira Riaz
Feb 12, 2024

Why are periods different lengths?

Due to the progressive filling of electron subshells.
Sawaira Riaz
Feb 12, 2024

Which period are alkali metals in?

Alkali metals are in various periods, but all in Group 1.
Sawaira Riaz
Feb 12, 2024

Can elements in the same group be in different states?

Yes, depending on the group.
Sawaira Riaz
Feb 12, 2024

Are noble gases a period or a group?

They are a group, Group 18.
Sawaira Riaz
Feb 12, 2024

What is the significance of group and period trends?

They help predict chemical behavior and properties of elements.
Aimie Carlson
Feb 12, 2024

What is a group in the periodic table?

A vertical column of elements with similar chemical properties.
Janet White
Feb 12, 2024

Do elements in the same group have the same atomic number?

No, atomic numbers increase down a group.
Sawaira Riaz
Feb 12, 2024

How does electron configuration change across a period?

Electrons fill higher energy levels as you move across a period.
Sawaira Riaz
Feb 12, 2024

What distinguishes one period from another?

The progressive filling of electron shells.
Janet White
Feb 12, 2024
About Author
Written by
Sawaira Riaz
Sawaira is a dedicated content editor at difference.wiki, where she meticulously refines articles to ensure clarity and accuracy. With a keen eye for detail, she upholds the site's commitment to delivering insightful and precise content.
Edited by
Huma Saeed
Huma is a renowned researcher acclaimed for her innovative work in Difference Wiki. Her dedication has led to key breakthroughs, establishing her prominence in academia. Her contributions continually inspire and guide her field.

Trending Comparisons

Popular Comparisons

New Comparisons