Chemistry Flashcards
Who was John Dalton?
Billiard Ball Model
All atoms of the same element are the same, but different then any other atom
Who was JJ Thomson?
Plum Pudding Model
Positive spheres with negative particles embedded in it
Who was Ernest Rutherford?
Discovered the nucleus
Small, dense, positive nucleus in the centre, surrounded by negative charges
Who was Neils Bohr?
Shells of Electrons
Electrons surround the nucleus in specific energy levels
2 electrons on the first energy level, 8 on every other level
Quantum Mechanical Model
Accepted today
Protons and neutrons in the nucleus at the centre
Electrons surround the nucleus, electrons are a cloud
What is mass number?
The total number of protons and neutrons in an atom
What is an electron?
Negative charge
Almost no mass
Orbit nucleus
What is a proton?
Positive charge
Found in nucleus
More mass
What is a neutron?
No charge
Found in nucleus
Same mass as protons
What is Atomic Number?
Number of protons the element has
What are Isotopes?
Atoms of the same element with the same number of protons, but different number of neutrons
What are valence electrons?
The outer most electrons
These electrons determine the properties of the atom
What are ions?
An atom that loses electrons becomes positive. These are called cations
An atom that gains electrons becomes negative. These are called anions
What are periods on the periodic table?
Horizontal rows that correspond to the number of energy levels around the atom
What are groups/families on the periodic table?
Vertical column which corresponds to the number of electrons on the last energy level
What are metals?
Most of the elements
Good conductors of electricity and heat
Malleable (stretchable)
Most are room temp. and shiny
What are non-metals?
17 elements
Do not conduct electricity or heat
Not malleable or ductile
Solid, liquid, and gases
What are metalloids?
All touch the staircase line (except aluminum)
Properties between metals and non-metals
What are the Alkali Metals?
Soft metals
Reactive
Group/Family 1 (except hydrogen)
What are the Alkaline Earth Metals?
Not as soft or as reactive as alkali metals
Group/Family 2
What are Noble Gases?
Extremely unreactive non-metals
Group/Family 18
What are the Halogens?
Very reactive non-metals
Only family with all three states
All are atomic
Group/Family 17
What are ionic compounds?
They are formed when a metal loses an electron to a non-metal and then are attracted to each other, forming an ionic bond
What are some rules for naming ionic compounds?
Name the cation: It’s just the elements name
Name the anion: Use the first part of the elements name and change the suffix to “ide”
Formulas must ensure charges balance out
What are polyatomic atoms?
A unit of more than one atom that behaves as a single ion
The charge is dispersed around the entire molecule and they do not break apart
Almost all are negatively charged
Most contain oxygen and their names end in “ate” or “ite”
What are the diatomic elements?
Hydrogen Nitrogen Fluorine Oxygen Iodine Chlorine Bromide
What are the polyatomic elements?
Sulfur (S8)
Phosphorus (P4)
What is the formula for water?
H2O
What is the formula for ammonia?
NH3
What is the formula for methane?
CH4
What is the formula for methanol?
CH3OH
What is the formula for glucose?
C6H12O6
What are some characteristics of molecular compounds?
Share electrons and form a covalent bond
Are composed of non-metals
Can be any state
Will not conduct electricity
Not all dissolve in water
Are always colourless
Have variable melting and boiling points
What are some characteristics of ionic compounds?
Transfer electrons to form an ionic bond
Are composed of a metal and a non-metal
Are solids
Will conduct electricity
Are soluble
Can be different colours
Have high melting and boiling points
What are some characteristics of acids?
Acids have a pH below 7
In water they form H+ (aq) ions
As the concentration of H+ (aq) ions increases, pH decreases
Taste sour, react with bases to produce water and an ionic compound
Conduct electricity in solution
React with most metal to produce hydrogen gas
What are some characteristics of bases?
Bases have a pH greater than 7
In water they form OH- (aq) ions
As the concentration of OH- (aq) ions decreases, pH increases
Taste bitter, react with acids to produce water and an ionic compound
How do acids and bases react with litmus paper?
Acids turn blue litmus paper red
Bases turn red litmus paper blue
What is matter?
Matter is any substance that takes up space by having mass or volume
What is the Law of Conservation of Mass?
During a chemical reaction, mass is neither created or destroyed
Mass of products = mass of reactants
What are physical properties of matter?
They describe physical appearance and composition of the substance
Boiling or condensation point Melting or freezing point Malleability Ductility Colour State Solubility Crystal formation Conductivity Magnetism
What are chemical properties of matter?
Describe reactivity of a substance
Ability to burn Flash point Behaviour in air Reaction with water Reaction with acids Reaction to heat Reaction to litmus paper
Pure substance
All particles are identical, properties are constant
Element
Cannot be broken down
Compound
Chemical combination of 2 or more elements
Mixture
Combination of pure substances
Solution
Is homogeneous because separate components are not visible
Heterogeneous
Different substances are visible (mechanical mixtures, suspensions, colloids)
What is a physical change?
The chemical components stay the same
No new substance is formed
What is a chemical change?
A new substance is formed
What is a precipitate?
It is a solid that formed from the reaction of 2 solutions
What is an endothermic and exothermic reaction?
Endothermic - energy is absorbed
Exothermic - energy is released
How to you identify chemical reactions?
Formation of precipitate Formation of bubbles (sometimes) Production of light Loss or gain of heat/energy Change in smell/taste Change in pH
Reactants
The chemicals that are initially put together and react
Products
The chemicals produced during a reaction
What are the five types of reactions?
Formation Decomposition Single Replacement Double Replacement Combustion
What is a formation reaction?
A substance is formed from its elements
Element + element = compound
What is a decomposition reaction?
A substance breaks down into its elements
Compound = element + element
What is a single replacement reaction?
An element reacts with a compound
Element + compound = new element + new compound
What is a double replacement reaction?
A compound reacts with a compound
compound + compound = new compound + new compound
What is a hydrocarbon combustion reaction?
“Burning” a compound, the compound reacts with oxygen to produce carbon dioxide and water vapour
Any hydrocarbon + oxygen = carbon dioxide + water vapour
What is molar mass?
The mass of one mole of a substance
The units for molar mass are grams per mole
The molar mass of an element can be found on the periodic table
