EOY Exam Essential Vocab Revision - Chemistry Flashcards
Molecule
Two or more non-metals and/or hydrogen bonded together. Eg: H2O, CO2, CH4
Compund
Two or more elements bonded together. (Note: A compound can be a molecule as well and vice versa). Eg: H2O, NaCl, CuFeS2
Element
One or more of the same atom(s), each having the same amount of protons and sharing similar properties, a pure substance. Eg: Ne, F2
Atom
The building blocks of matter, the smallest particles of a chemical element.
Proton
A positively charged subatomic particle present in the nucleus of an atom. The protons have a similar atomic weight to neutrons. The protons determine the element of the atom, eg; 8 protons means the atom is an oxygen.
Electron
A negatively charged subatomic particle present in the atomic cloud of the atom, often rearranged in shells/energy levels. Electrons are about 1800th size of a proton
Neutron
Neutrons are neutrally charged subatomic particles found in the nucleus of an atom. The amount of neutrons cam affect the isotope of the element. Neutrons are about the same size of protons
Nucleus
The centre of an atom, consisting of neutrons and protons
Atomic Number
The amount of protons in an atom, which decides what element it is.
Atomic Mass
The atomic mass is the total mass of the atom, which can be found by adding up the amount of protons and neutrons. The relative atomic mass is the average weight of all the element’s isotopes, using the percentage of the isotopes present in nature
Isotope
Isotopes are the different form of an element, possessing slightly different properties, and the isotope is decided by the amount of neutrons present. Eg; Original carbon atom is called Carbon-12 (as it has an atomic mass of 12) whereas an isotope of carbon is called Carbon-14 (as there are two extra neutrons, increasing the atomic weight to 14)
Electron Shells
Sometimes referred to as energy levels, are shell(s) that are arranged and hold certain amount of electron(s).
Metals and their properties
Mostly found in the left side of the periodic table. Elements that have certain properties, such as:
* Good conductors of heat and electricity
* Posses a high Melting Point and Boiling Point
* Usually posses lustre (shine)
* Ductile (Able to be drawn out into a wire)
* Malleable (Able to be beaten up, bent or flattened into shape)
* Mostly found in a solid state
Non-Metals and their properties
Mostly found towards the right end of the periodic table. Elements that do not posses properties of metals.
Metaloids
Elements that contain features from both metals and non-metals. Examples include; Boron, silicon, germanium, etc.
Noble gasses
Non reactive elements that posses a full valence shell. Found in Group 8. Examples include; Helium, Neon, Argon, Krypton, xenon, etc
Halogens
Reactive non-metals found in Group 7. Examples include; Fluroine, Chlorine, Bromine, Iodine, etc.
Groups and what they tell you
In a periodic table
Columns in the periodic table. Elements in a group have similar properties. The group number tells you the amount of valence electrons.
Period and what they tell you
Rows found in the periodic table. Periods tell you have many shells the elements posses
Alloy
A metal formed by bonding together one or more metals together, or bonding between metals and non-metals. The new substance formed has different properties.
Chemical Bonding
Elements bonded together through either metallic, ionic or covalent bonding.
Lattice
referring to chemically bonded compunds
The pattern or structure of a bonded compound to form crystal like structures.
Chemical Formula
A small, shortened way of writing a chemical’s name using symbols of elements and subscripted numbers to represent the number of atoms for the element. Eg; The chemical formula for water (dihydrogen monoxide) is H2O
Structural Formula/Diagram
Diagram that shows the structure of a compound or molecule, using lines to connect elements, each line representing a pair of electrons. Lone pairs of electrons are represented by a line that doesn’t connect to any other element. Bonds have to be drawn in the correct position. This diagram is used for covalent bonding. Only the valence electrons from the valence shell are shown in the diagram.
Dot Diagram
Diagram that shows the structure of a compound or a molecule, using pairs of dots to represent either lone pairs of electrons or shared electrons. Pairs of electrons must be drawn in correct position. This diagram is used for covalent bonding. Only the valence electrons from the valence shell are shown in the diagram.
Metallic Bonding and lattice
Metallic bonding consists of the bonding of one or more metals. The lattice of metallic bonding consists of 3D orderly patterned positive cations surrounded by a negatively charged sea of delocalised electrons that are free flowing.
Sea of Delocalised Electrons
Consists of the electrons that a metal sheds in order to become a stable cation with a full valence shell. These electrons are no longer bound to any singular cation, but flow freely around. The Sea of Delocalised electrons gives the metals it’s properties.
Ion
Atoms that have lost or gained electrons in order to have a full outer shell, and now carry an electrical charge. Cations are positively charged (lost electrons) and anions are negatively charged (gained electrons)
Ionic Bonding and lattice
“The connecting of charged atoms” Ionic bonding is the bonding between metals and non-metals, through the transfer of electrons resulting in cations and anions that are held together in an electrostatic charge. The lattice of ionic bonding is brittle, as it consists of positive cations and negative cations placed alternatively in a 3D pattern, and held together by an electrostatic charge
Ionic Bond & Electrostatic Charge
The attractive force between ions with opposite charges, resulting in the creation of a bond.
Lone Pairs
Pairs of valence electrons that are involved in chemical reactions and/or bonding
Covalent Compounds
Compounds that consist of elements held together by covalent bonds
L-Rule
The L rule tells you the non-metal elements Nitrogen, Oxygen, Fluorine, Chlorine, Bromine and Iodine form pairs with themselves using covalent bonding. These elements create an “L” shape on the periodic table.
Valence Shell
Outermost electron shell
Valence Electrons
Electrons found on outer-shell, and often involved in chemical reactions and bonding
Octete Rule
The tendency of atoms to give or gain electrons in order to have 8 electrons in their outer shell (to usually act as a full outer shell)
Electron Configuration
An ordered list of numbers that shows the amount of electrons present in each shell, starting from the innermost shell (lower energy level) to the outermost shell (higher energy level). Eg: Electron configuration of potassium is 2,8,8,1
Reaction rate
The rate at which a reaction takes place, which can be affected by various factors. Examples of reaction rate are: Increase in heat, Increase exposure to surface area, increase concentration and a catalyst (a substance that helps speed a reeaction without taking part in it)
Chemical Reaction
The reaction between two or more atoms that alters the chemical arrangement to form a new substance or substances
Aqueous Solution
Solutions where the solvent is water and the substance has been dissolved.
Brittle
Easily breakable, and breaks into many pieces. (Often used to describe ionic compunds/lattice)
Electron Shell Formula
2*n^2
Three types of covalent bonds
Single bond, double bond and triple bond
Exothermic Reaction
Absorbs heat from environemnt and temperature drops. Heat energy converted to chemical energy.
Exothermic reaction
Releases heat into the environment and temperature increases. Chemical energy converted to heat energy.
Spontaneous/Instantaneous Reaction
Reaction that occurss immediately after the two reactants come into contact and don’t require a kick start.
Precipitate
A solid product, often accompanied in a liquid, that forms after a precipitation reaction occurs
pH scale
Describes the acidity or basicness of substances on a scale of 1-14. 7 is netral, below seven is acidic and above seven is basic.
Acid-Base Reaction
When an acidic reactant reacts with a basic reactant to form a neutral result. the result consists of a salt and water. The process of this reaction is called neutralisation as the products are neutral on the pH scale.
Word Equation
Describes the reactants and products in full written names, with no numbers or values
Chemical Equation
Equation written using chemical formulas and values to represent amount of atoms/molecules/compounds
Precipitation Reaction
When two aqueous solutions react to form a solid (ionic solid) and liquid products
Reactants
Substances that react together in a chemical reaction
Products
The new resulting substance(s) of reactants reacting in a chemical reaction
Physical Change vs Chemical Change
Physical change is a mere chaneg in shape, size or state whereas chemical change is when one or more new substances are produced
Soluble
Ability of a substance to disolve in water
Redox Reaction
Oxidation-reduction Reactions
Redox reactions involve a tranfer of electrons and come in the form of:
* burning/combustion reactions
* corrosion
* batteries and cells
Characteristics of Metals
- Conductors
- Usually solids
- Lustrous (shiny)
- Malleable (Able to be shaped)
- Ductile (Can be drawn into wire)
- High Melting/Boiling Point
