S-block Facts for Kids

The s-block is a special group of chemical elements in the periodic table. Think of the periodic table like a big map of all known elements. This map is divided into different "blocks" based on where an element's outermost electrons are found. For s-block elements, these important outer electrons are in a place called the "s-orbital."

The s-block includes elements from the first two groups of the periodic table.

Elements in Group 1 are called alkali metals.
Elements in Group 2 are called alkaline earth metals.

The modern periodic law helps us understand why elements are grouped this way. It says that the properties of elements repeat in a pattern as their atomic number (the number of protons in an atom) increases. This repeating pattern helps scientists organize elements into blocks like s-, p-, d-, and f-.

What are the s-block elements?
Amazing properties of s-block elements
What is a diagonal relationship?
- Why is Lithium special?
Related pages
See also

What are the s-block elements?

The s-block elements include:

Group 1 (Alkali Metals): Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Caesium (Cs), and Francium (Fr). Hydrogen (H) is also in Group 1 but is not an alkali metal.
Group 2 (Alkaline Earth Metals): Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).
Helium (He) is also considered an s-block element, even though it's in Group 18 (the noble gases).

Amazing properties of s-block elements

Most s-block elements are metals, except for Hydrogen. They are usually shiny and silvery. They are also good at letting heat and electricity pass through them.

One of their most important features is how easily they lose their outer electrons. These are called "valence electrons." Because they lose these electrons so easily, s-block elements are some of the most reactive elements on the periodic table!

How do alkali metals behave?

The elements in Group 1 (except hydrogen) are known as the alkali metals. They always lose their single outer electron to form an ion with a +1 charge.

These metals are silvery, very soft, and not very dense.
They have low melting points, meaning they turn into a liquid easily with a little heat.
Alkali metals react very strongly with water and even with oxygen in the air. This reaction can produce a lot of energy and hydrogen gas, which can catch fire!
Because they are so reactive, alkali metals are often stored in mineral oil or kerosene. This keeps them from reacting with air or water.

How do alkaline earth metals behave?

The elements in Group 2 (except helium) are called the alkaline earth metals. They always lose their two outer electrons to form an ion with a +2 charge.

Like alkali metals, they are silvery, shiny, and quite soft.
Some alkaline earth metals also react strongly with water, so they need to be stored carefully.

S-block elements in fireworks

S-block elements are famous for making fireworks colorful!

When potassium is heated, it can create brilliant purple colors.
Strontium gives fireworks a bright red color.
Barium helps create vibrant green displays.

The rarest s-block element: Francium

Francium is an incredibly rare element. Scientists believe that at any given moment, there might only be one natural atom of Francium on Earth! Francium is also very unstable. Its atomic nucleus breaks apart quickly in a process called radioactive decay.

What is a diagonal relationship?

Sometimes, elements in the periodic table show a "diagonal relationship." This means that the first element in a group can behave similarly to the second element in the next group.

For example, Lithium (Li) in Group 1 is similar to Magnesium (Mg) in Group 2.
And Beryllium (Be) in Group 2 is similar to Aluminium (Al) in Group 13.

This happens because these elements have similar sizes of their ions. For example, Lithium and Magnesium ions are very close in size:

Lithium (Li) ion radius: 152 picometers (pm)
Magnesium (Mg) ion radius: 160 picometers (pm)

Why is Lithium special?

Lithium is the first element in Group 1, but it acts a bit differently from the other alkali metals. This is mainly because:

It has a very small atom and ion size.
Its compounds tend to be more "covalent," meaning they share electrons more, which affects how they dissolve in liquids.
It has stronger bonds between its atoms.

Here are some ways Lithium is different:

Hardness: Lithium is harder than sodium and potassium. Sodium and potassium are so soft you can cut them with a knife!
Melting and Boiling Points: Lithium has higher melting and boiling points than other alkali metals.
Reaction with Oxygen: Lithium forms a simple monoxide when it reacts with oxygen. Other alkali metals can form more complex compounds like peroxides and superoxides.
Reaction with Nitrogen: Lithium can combine with nitrogen gas to form nitrides. Most other alkali metals do not do this.
Hydrates: Lithium chloride (LiCl) can absorb water from the air and form a hydrate (LiCl·2H₂O). Other alkali metal chlorides do not form these types of hydrates.

Electron configuration
NCERT SOLUTIONS THE S-BLOCK ELEMENTS

S-block facts for kids

Contents