SPM Form 4: Periodic Table of elements (Checklist)

• Periodic Table: the table showing the elements in order of increasing proton number; similar elements are arranged in columns called groups.
• Group: A vertical column of elements in the Periodic table.
• Period: A horizontal row of the Periodic Table; its number tells you how many electron shells there are.
• Alkali metals: the Group I elements of the Periodic Table, which include lithium, sodium, potassium, rubidium, caesium and francium.
• Alkaline earth metals: the Group II elements of the Periodic Table, which include beryllium, magnesium, calcium, strontium, barium, and radium.
• Halogens: the Group VII elements of the Periodic Table, which include fluorine, chlorine, bromine, iodine and astatine.
• Noble gases: the Group 18 elements of the Periodic Table; they are called ‘noble’ or inert gases because they are so unreactive, which include helium, neon, argon, krypton, xenon and radon.
• Transition elements: the elements in the wide middle block of the Periodic Table (elements in group 3 to group 12).
• Metal: an element that shows metallic properties (for example conducts electricity, and forms positive ions)
• Non-metal - an element that does not show metallic properties: the non-metals lie to the right of the zig-zag line in the Periodic Table.
• Amphoteric oxide: An oxide that exhibits both acidic and basic properties.
• The atomic radius is a term used to describe the size of the atom.
• The ionization energy is the energy required to completely remove an electron from a gaseous atom or ion.
• Electron affinity reflects the ability of an atom to accept an electron. It is the energy change that occurs when an electron is added to a gaseous atom.
• Electronegativity is a measure of the attraction of an atom for the electrons in a chemical bond. The higher the electronegativity of an atom, the greater its attraction for bonding electrons.

Uses of the noble gases

The noble gases are unreactive or inert, which makes them safe to use. They also glow when a current is passed through them at low pressure. These properties lead to many uses:

• Helium is used to fill balloons and airships, because it is much lighter than air – and will not catch fire.
• Argon is used to provide an inert atmosphere. For example it is used: as filler in tungsten light bulbs and to protect metals that are being welded.
• Neon is used in advertising signs. It glows red, but the colour can be changed by mixing it with other gases.
• Krypton is used in lasers – for example for eye surgery – and in car headlamps.
• Xenon gives a light like bright daylight, but with a blue tinge. It is used in lighthouse lamps, lights for hospital operating rooms, and car headlamps.

Why noble gases chemically inert?

Helium has a duplet electron arrangement whereas other noble gases have octet electron arrangements. These electrons arrangements are very stable. Hence, atoms of noble gases do not release electrons, accept electrons or share electrons with other atoms. Thus, they are chemically inert. 

Why is neon exists as a monoatomic gas?

• Neon is from the Noble Gases group on the periodic table. 
• Neon has electron arrangement is 2.8 (valence electron is 8). 
• Neon already achieves the octet electron arrangement. 
• Neon does not need to donate the electron with other element. 
• Therefore they do not gain or lose electrons making them exist as individual atoms. 
• Neon exists as a monoatomic gas. 

Why the boiling point of noble gases increases when going down the group?

The boiling point of noble gases increases when going down Group 18. This is because the atomic size of noble gases becomes bigger when going down Group 18. Thus, the forces of attraction between atoms become stronger when going down Group 18. More heat energy is required to overcome the forces between atoms. This causes the boiling point of noble gases to increases when going down Group 18. 

Overview of Periodic Table

• Alkali Metals (Group 1) : All group 1 metals have one valence electron. When they form ions, they will have a charge of 1+. Group 1 alkali metals are highly reactive and will react vigorously with water.

• Alkali Earth Metals (Group 2): All group 2 metals have two valence electrons. When they form ions, they will have a charge of 2+. Group 2 alkaline earth metals are highly reactive and will react with water.

• Transition Metals (Groups 3–10, d block): Transition metals are famous for the colored salts and colored solutions they form. Many gems contain numerous transition metals. It is hard to predict the charge of a transition metal ion because the transition metals have multiple oxidation states. One transition metal, Hg, exists as a liquid at room temperature.

• Halogens (Group 17): Halogens (salt formers) have seven valence electrons and form ions with a charge of 1−. The halogens exist in three phases at room temperature. Fluorine is a pale-yellow gas, chlorine is a green gas, bromine is a brown-orange liquid, and iodine is a purple solid.

• Noble (Inert) Gases (Group 18): Noble gases have a full outer shell and will not react to form ions or share electrons.

• Lanthanides and Actinides (f Block): These elements have their valence electrons located in the f orbitals and are radioactive in nature.

Noble Gases on the Periodic Table

The noble gases, also known as the inert gases, are located in Group VIII of the periodic table. The noble gases are helium, neon, argon, krypton, xenon, radon. The noble gases are relatively non-reactive because they have a complete valence shell. They have little tendency to gain or lose electrons. The noble gases have high ionization energies and negligible electronegativities. The noble gases have low boiling points and are all gases at room temperature.

Summary of Common Properties

·         Fairly nonreactive

·         Complete valence shell

·         High ionization energies

·         Very low electronegativities

·         Low boiling points (all gases at room temperature)