4.5 Elements in a period

Properties of elements across Period 3
■ Period

	►	The horizontal rows in the Periodic Table of Elements.
	►	The proton number increase by one across the period from left to right.

■ Properties of elements across Period 3

	►
	►	The physical and chemical properties of the elements change gradually across the period as in the following table: Element properties Na Mg Al Si P S Cl Ar Electron arrangement 2.8.1 2.8.2 2.8.3 2.8.4 2.8.5 2.8.6 2.8.7 2.8.8 Electron valence 1 2 3 4 5 6 7 8
	►	The animation below shows the explanation on the properties changes across Period 3.

■ This video contains information about the properties changes across Period 3.

Laboratory Activity 4.5.1: Determining the properties of oxide of elements in Period 3

✍ Worked-example 4.5(a)
Choose true[ √ ] or false[ X ] for the statement given.

Statement	Answer
The proton number increases by one across the period from left to right in the Periodic Table.	✔
The atomic radius increases across the period from left to right in the Periodic Table.	✘
The electronegativity increases across the period from left to right in the Periodic Table.	✔
The melting point and boiling point increase and then decrease across the period from left to right in the Periodic Table.	✔
The element oxide turns from basic to amphoteric and then to acidic across the period from left to right in the Periodic Table.	✔

← 4.4 Group 17 Elements

4.6 Transition Elements →

⇲ For exercise(objective and subjective), download for free on Android OS.