Chemistry Revision Booklet

Chemistry: Reflection Booklet Wednesday, May 13th, 2015

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Exam Revision Booklet This booklet contains the revision for all the exam topics including detailed

specifications.

Chapter 1: Atomic Structure Wednesday, May 13th, 2015

Chapter 1: Atomic Structure The Structure of the atom

Atom: The smallest particle of a chemical element that can exist.

Molecule: A group of atoms bonded together [Extra: representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.]

Elements: Elements are chemically the simplest substances and hence cannot be broken down using chemical methods

Compound: A compound is a substance formed when two or more chemical elements are chemically bonded together.

Mixture: A mixture contains two or more substances that are not chemically combined.

Atomic Number and Mass number

Isotopes

Isotopes: are atoms with same Atomic # (# of protons) but dierent Mass # (# of neutrons).

Half Life: Time taken for half of a radio active element to decay.( Usually in a: Years)

Calculating average mass of isotopes;

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Amount Charge

Protons 54 +

Electrons 54 -

Nutrons 77 0 (None)

Ar 131 /

30% Cl3

70% Cl2


Arrangement of Electrons

Law of Conservation of Mass

The Law of Conservation of Mass: States that mass is neither created nor destroyed in any ordinary chemical reaction.

Drawing Diagrams of Electronic Configuration

The Periodic Table of Elements

Group: Going down the periodic table. (Vertically)

Period: Going along the periodic table. (Horizontally)

Elements in the same group have similar chemical properties.

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Down Group I: Earth Metals - Force of attraction decreases.

- Mass Increases.

- Colors lighten.

- Reactivity increases.

- Density decreases.

- Solid>Liquid>Gas.

Down Group VII: Halogens - Force of attraction increases.

- Mass Increases.

- Colors darken.

- Reactivity increases.

- Density increases

- Gas>Liquid >Solid.

Group 0: Nobel Gases/ Inert Gases - Elements in group zero have a full outer shell, so they do not react with any other

element, unless under specific conditions.

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Chapter 2: Bonding Wednesday, May 13th, 2015

Chapter 2: Bonding

Covalent Bonding

Covalent Bond: A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs and the stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding.

Formation: Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.

Properties:

- Strong attraction between the nuclei and shared pairs of electrons.

- Molecules:

- H2 - F2 - Cl2- Simple molecular Structure. - Not Conductive

Dot cross diagrams:

The formation of covalent compounds using dot cross diagrams by electron sharing.

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Simple molecular structures:

- Substances with simple molecular structures are either gases or liquids (rarely solids)

with low melting points.

- Relatively weak forces between the molecules making it eyes to break those weak

forces with heat.

Giant Covalent Structures:

Diamond Diamond is made from carbon atoms being strongly bonded together.

Properties:

- Diamond has strongly bonded atoms.

- All the elements are bonded together with a covalent

structure; forming a network.

Graphite Graphite is made from carbon atoms strongly bonded together, but it has weak intermolecular forces.

Properties:

- Graphite has strongly bonded atoms.

- All the elements are bonded together with a

covalent structure; forming a network.

- Every carbon in diamond is bonded to four

other carbons but graphite only bonds to three hence why it has free electrons.

Silicon dioxide Diagram

Giant covalent structures have high melting and boiling points since the have many strong bonds between the atoms that would require large amounts of heat (kinetic) energy to break.

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Ionic Bonding

Ionic Bond: Is the electrostatic force of attraction between oppositely charged ions.

Formations: Ionic bonding can result from a redox reaction when atoms of an element (usually metal), whose ionization energy is low, release some of their electrons to achieve a stable electron configuration. In doing so, cations are formed.

Ionic Compound: An ionic compound is a chemical compound in which ions are held together in a structure by electrostatic forces termed ionic bonds. The positively charged ions are called cations and the negatively charged ions are called anions.

Properties: - The force of attraction between the ions:

- Strong.

- State: Solid/Crystal.

- Malleability: None.

- Melting Point: High.

- Boiling Point: High.

- Conductivity: *Only when

- Molten.

- Aqueous.

- Mobile electrons required.

Oxidation: The loss of electrons, causing the net charge to be positively charged since there would be more protons.

Reduction: The gain of electrons, causing in the net charge to be negative since there would be more electrons than protons.

Dot and cross diagrams:> The formation of ionic compounds using dot cross diagrams by electron transfer.

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Metallic Bonding

Metallic Bonds: Metallic bond is the bonding between molecules within metals. It is the sharing of a sea of delocalized electrons amongst a lattice of positive ions, where the electrons act as a "glue" giving the substance a definite structure.

Properties:

- Electrons are held loosely.

- Nuclei are surrounded by free electrons.

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Chemistry Revision Booklet