The Periodic Table

The Periodic Table

Define a group.

A vertical column in the Periodic Table.

Define a period.

A horizontal row in the Periodic Table.

Why do elements in the same group have similar chemical properties?

They have the same outer electronic configuration.

What do elements in the same period have in common?

They have the same number of occupied quantum shells.

What determines the chemical properties of an element?

Its electronic configuration.

What does n represent in an outer electronic configuration?

The number of the outer quantum shell.

What is the general outer electronic configuration of Group 1?

ns¹

What is the general outer electronic configuration of Group 2?

ns²

What is the general outer electronic configuration of Group 3?

ns²np¹

What is the general outer electronic configuration of Group 4?

ns²np²

What is the general outer electronic configuration of Group 5?

ns²np³

What is the general outer electronic configuration of Group 6?

ns²np⁴

What is the general outer electronic configuration of Group 7?

ns²np⁵

What is the general outer electronic configuration of Group 8?

ns²np⁶

What does n equal for elements in Period 2?

n = 2.

What does n equal for elements in Period 3?

n = 3.

What are blocks in the Periodic Table?

Regions of the Periodic Table classified according to the type of orbital or sub-shell being filled with electrons.

What are the three main blocks shown in the Periodic Table?

The s-block, p-block and d-block.

What determines which block an element belongs to?

The type of orbital associated with its highest-energy electrons or the sub-shell being filled.

Define an s-block element.

An element whose highest-energy electron is in an s orbital.

Which groups make up the s-block?

Groups 1 and 2.

What is being filled across the s-block?

The s sub-shell.

Define a p-block element.

An element whose highest-energy electrons are in p orbitals.

Which groups make up the p-block?

Groups 3 to 8.

What is being filled across the p-block?

The p sub-shell.

Define a d-block element.

An element in which the d sub-shell is being filled.

Where is the d-block located in the Periodic Table?

Between the s-block and p-block.

Which elements form the first row of the d-block?

Scandium to zinc.

Which elements form the second row of the d-block shown?

Yttrium to cadmium.

What happens to the number of electrons in the d orbitals across the d-block?

It generally increases from left to right.

Why can the d-block not be defined in exactly the same way as the s- and p-blocks?

The electrons in the d orbitals may have lower energy than electrons in the outer s orbital.

What is an example of this energy relationship in the first row of the d-block?

The 3d sub-shell has lower energy than the 4s sub-shell for the d-block elements.

Why are lithium and sodium in the same group?

They have the same type of outer electronic configuration, ns¹.

Why are fluorine and chlorine in the same group?

They both have an outer electronic configuration of ns²np⁵.

Why are lithium and neon both in Period 2?

Their occupied electrons extend to the second quantum shell.

Why are sodium and argon both in Period 3?

Their occupied electrons extend to the third quantum shell.

How can you predict an element's group from its outer electronic configuration?

Use the number of outer-shell s and p electrons; for main-group elements this corresponds to its group number.

How can you predict an element's period from its electronic configuration?

Identify the highest occupied principal quantum shell.

How can you identify an s-block element from its electronic configuration?

Its highest-energy electron occupies an s orbital.

How can you identify a p-block element from its electronic configuration?

Its highest-energy electrons occupy p orbitals.

How can you identify a d-block element from its electronic configuration?

Its d sub-shell is being filled.

Carbon has an outer electronic configuration of 2s²2p². Which group is it in?

Group 4.

Carbon has an outer electronic configuration of 2s²2p². Which period is it in?

Period 2.

What is the outer electronic configuration of arsenic?

4s²4p³.

How can you predict the outer electronic configuration of arsenic?

Arsenic is in Group 5 and Period 4, so its outer configuration is ns²np³ where n = 4, giving 4s²4p³.