How are the trends of atomic radius and ionization energy related? Explain in both groups and periods.

These trends are inverses of each other. As the size of the atom increases, the ionization energy (energy required to remove the electron) decreases because the electron being removed is farther from the nucleus in a larger atom.Less energy is required to remove an electron further from the nucleus. [AR increases down a group while IE decreases; AR decreases across a period while IE increases.]

What’s the difference between electronegativity and ionization energy?

Electronegativity is related to the pull of a nucleus on an electron being shared in a bond. Ionization energy is the energy required to remove an electron from an unbonded atom. Electronegativity is a ranking and has no units. Ionization energy is an amount of energy and has units such as kilojoules.

Atomic Radius Trends

Why are atoms larger going down a group
Atoms get larger because the higher the energy level, the more orbitals it has and the further away from the nucleus those orbitals are. Also, more electrons are interfering with the attraction that the nucleus has on the highest energy electrons [shielding].

Why do atoms get smaller going from left to right across the table.
Atoms get smaller because there is an increase in the effective nuclear charge [more protons attracting more electrons) so the highest energy level get pulled in closer to the nucleus.

What are metalloids? State the properties of metalloids and list all the metalloids on the Periodic Table.

Metalloids are elements that lie along the zigzag line on the periodic table starting with Boron and moving down in steps. These elements share properties of both metals and non-metals. Metalloids are solids, ductile and malleable.  These are good semiconductors. At high temperatures metalloids acts like metals and conduct electricity. At lower temperatures metalloids act like nonmetals and stop electricity from flowing. This property is useful in electronic devices such as computers, tv's and solar cells. The metalloids include: Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, and Polonium.

State three differences between an ionic compound and a covalent compound

Three differences between an ionic compound and covalent compound are:

•  An ionic compound has high boiling and melting point whereas covalent compound has low melting and boiling point. 
• An ionic compound is soluble in water but is insoluble in organic solvents, whereas a covalent compounds is soluble in organic solvent but is insouble in water.
• An ionic compounds conducts electricity in the liquid state and in aqueous solution whereas a covalent compounds does not conduct electricity in any state. 

SPM Form 5: Chemicals for Consumers (Checklist)

• Saponification: Alkaline hydrolysis of an ester where the ester is boiled with sodium hydroxide, NaOH or potassium hydroxide, KOH solution to produce an alcohol and a sodium or potassium salt of a carboxylic acid.
• Soap is not an effective cleansing agent in hard water but is only effective in soft water. Detergent is an effective cleansing agent in both hard water and soft water.  
• Soft water: Water that does not contain mineral salts such as magnesium salt or calcium salts.
• Hard water: Water that contain mineral salts.
• Food additives are substances added to food to preserve flavor or enhance its taste and appearance. Types of additives are preservatives, antioxidants, flavourings, stabilizers, thickening agents and food dyes (colourings).
• Medicines: a compound or preparation used for the treatment or prevention of disease, especially a drug or drugs taken by mouth. Types of modern medicines are analgesics, antibiotics, stimulants, antidepressant and antipsychotic. 

SPM Form 5: Carbon compounds (Checklist)

• Organic compounds: Carbon-containing compounds that can be obtained from living things.
• Inorganic compounds: Non-carbon-containing compounds that can be obtained from non-living things.
• Hydrocarbons: Compounds that contain only carbon and hydrogen. In a saturated hydrocarbon, all the bonds are single bonds. Alkane is another name for a saturated hydrocarbon. Unsaturated hydrocarbons are a hydrocarbon that contains one or more double or triple bonds are an unsaturated hydrocarbon. There are three types of unsaturated hydrocarbons alkenes, alkynes, and aromatic hydrocarbons.
• Alkanes: Hydrocarbons having the general formula C_nH_2n+2, where n = 1, 2
• Alkenes: Hydrocarbons that contain one or more carbon-carbon double bonds. They have the general formula C_nH_2n.      
• Alcohol: An organic compound containing the hydroxyl group -OH.
• Aldehydes: Compounds with a carbonyl functional group and the general formula RCHO, where R is an H atom, an alkyl, or an aromatic group.       
• Carboxylic acids: Acids that contain the carboxyl group -COOH.
• Esters: Compounds that have the general formula R’COOR, where R’ can be H or an alkyl group or an aromatic group and R is an alkyl group or an aromatic group.
• Homologous series: A series of compounds in which each member differs from the next by a specific number and kind of atoms.
• Esterification: A reaction between an alcohol and a carboxylic acid in the presence of concentrated sulphuric acid as a catalyst through boiling to produce an ester and water. e.g. reaction of ethanol, C₂H₅OH with ethanoic acid, CH₃COOH in the presence of concentrated sulphuric acid, H₂SO₄ produces ethyl ethanoate, CH₃COOC₂H₅ which is an ester with a pleasant fragrant smell.
• Fats: Solid triester of glycerol and mostly saturated fatty acids.
• Vulcanization of rubber:  A process whereby rubber is reacted with sulphur to enable the formation of cross-linkages by sulphur atoms between the rubber molecules through covalent bonds. Rubber can be vulcanized by dipping natural rubber sheets into disulphur dichloride solution in methylbenzene. Vulcanized rubber is hard whereas unvulcanized rubber is soft. Vulcanized rubber is more elastic than unvulcanized rubber.
• Coagulation of latex: A process of converting liquid latex to solid natural rubber by adding an acid. Coagulation of latex occurs rapidly when an acid is added to the latex. Latex does not coagulate when an alkali is added to the latex. Alkaline solutions contain hydroxide ions which neutralize the acid produced by bacteria. Hence, it prevents the latex from coagulating.