PERIOD 3

The table shows the elements X and Y with their proton numbers. Between elements X and Y, which is more electronegative? 

Element Y is more electronegative than element X. Why?

• Atomic sizes Y is smaller than the atomic size of atom X

• Attraction force of nucleus towards valence electron is stronger for atom Y

• Atom X is easier to receive one electron to achieve the electron arrangement of inert gas

Why are the elements sodium, Na, magnesium, Mg, aluminium, Al, silicon, Si, phosphorus, P,sulphur, S, chlorine, Cl and argon, Ar in the same period?

• These elements have three valence electrons

• These elements have three physical properties

• These elements have three electron shells

• These elements have three electron

Some of the elements in period 3 are

• Sodium, Na

• Magnesium, Mg

• Oxygen, O

• Argon, Ar

Silicon exists as a solid at room temperature while non-metals like chlorine exists as a gas. Explain.

• Silicon has high melting point and boiling point.

• Chlorine has low melting point and boiling point.

• Chlorine has high melting point and boiling point.

• Silicon has low melting point and boiling point.

Figure 4.15 shows several elements in the Periodic Table of Elements.When aluminium and chlorine are compared, which element has a smaller atomic size?

Which element forms an amphoteric oxide?

When crossing Period 3 from left to right

• the elements become less electronegative

• the metallic properties increases

• the atomic radius become smaller

• the proton number of elements decrease

What is the electron arrangement for aluminium,Al?

Based on the above information, it can be concluded that aluminium oxide is

• an amphoteric oxide

• a basic oxide

• an acidic oxide

• a metalloid oxide