all matter is made up of atoms, atoms are made up of smaller particles. The fundamental building blocks of chemistry
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Nucleus
The central part of an atom
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Protons
Positively charged particles found in the nucleus
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Neutrons
Neutral particles found inside the nucleus
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Electrons
Negatively charged particles that orbit the nucleus
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In each atom the number of protons will always be the same number of \_______
electrons ( to ensure the overall charge is zero )
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Element
a substance that is made up of just one type of atom. There are over 100 been discovered
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Atomic number
this is the number of protons inside the nucleus of an atom
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Mass number
this is the number of protons and neutrons in the nucleus of an atom
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To calculate the number of neutrons
Mass number (top) - atomic number (bottom)
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The Atomic number is ALWAYS the \_______ number next to the element. The mass number is always the \______ number.
smaller, bigger
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How many electrons in shell 1
2
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How many electrons in shell 2
8
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How many electrons in shell 3
8
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How many electrons in shell 4
Whatever is left
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Ion
An atom with a charge
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If an atom loses an electron it becomes
positively charged
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If an atom gains an electron it becomes
negatively charged
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Cation
A positively charged ion
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Anion
A negatively charged ion
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Metals lose electrons to become
positive ions (cations)
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Non- Metals gain electrons to become
negative ions (Anions)
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Who created the periodic table
Dmitri Mendeleev (Russian) based on the properties of Elements known in 1869
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How many elements in the periodic table
118 (92 naturally occuring)
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The periodic table is organised based on \______
atomic number (number of protons)
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Atoms with the same atomic number have \__________
identical properties
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Groups are the \_________
columns
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Periods are the \__________
rows
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Mass number \= \_________ + \__________
protons + neutrons in an atom
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Group 1 on the periodic table
Alkali metals (very reactive with water)
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Group 2 on the periodic table
Alkali Earth metals
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Group 7 (aka 17) on the periodic table
Halogens (brightly coloured)
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Group 8 (aka 18 or 0) on the periodic table
Noble Gases (very unreactive)
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The block in the middle
Transition metals
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Group 1 elements all have \___ electron in the outer shell
one
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Group 2 elements have \___ in the outer shell
two
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Group 7 elements have \______ in the outer shell
seven
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Group 8 (aka group 18 or 0) have a \________ outer shell
complete
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valance shell
The outermost shell
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valence electrons
The electrons in the valence shell
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Compound
two or more elements chemically bonded
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Ionic bond
The two atoms are attracted to each other due to opposite charges
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What do ionic compounds have in common?
•Made of positive and negative ions
•Usually solid at room temperature
•High melting points because ionic bonds are very strong
•Dissolve in water to form aqueous solutions. Aqueous solutions conduct electricity
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Atoms can achieve a full outer shell of electrons by \________
sharing
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Covalent bond
Non-metals share electrons to form covalent bonds
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Electron Dot Diagrams
Diagrams to show how valence electrons and how they are shared
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Covalent Compound Properties
•Exist as gas, liquids or solids with low melting points as covalent bonds are weak
•Generally don't conduct electricity because they aren't made of ions
•Usually don't dissolve in water
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Metallic bonding
Occurs when a group of metal atoms shares a cloud of valence electrons
* sea of free floating valence electrons * not attached to any one atom * free to move
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Metallic bonding properties
malleable, ductile, good conductor of heat and electrons
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Mineral ores
When Earth formed, reactive metals (Al, Zn, Cu and Fe) reacted with other elements to form
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Reactivity of metals
how easily metals give away their outer electron
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metal + acid \=
salt + hydrogen gas
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Properties of metals
* Luster = shiny * Sonorous = ringing sound * Ductile = stretched into wires * Malleable = bent into shape * conductivity = heat and electricity travel through easily * High melting point = can be used in high temperatures
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To name simple compounds of metals and non-metals:
1. Write down the name of the metal. 2. Write down the name of the non-metal, changing the ending of the word to "-ide".
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Naming compounds containing oxygen
For compounds containing two elements plus oxygen, the ending of the other non-metal usually changes to "-ate".
e.g. nickel + sulfur + oxygen = nickel sulfate
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Chemical bond
An attractive force that holds two atoms together. Chemical bonds are broken or formed during chemical reactions.
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delocalised
Able to move freely from one place to another. The valence electrons in metals are delocalised so they can move freely between atoms.
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electron configuration
The arrangement of electrons in shells around an atom's nucleus. Nitrogen has the configuration 2.5 while magnesium has the configuration 2.8.2.
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electron shell
A grouping of electrons around the nucleus of an atom. Electron shells increase in energy level with distance from the nucleus.
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lattice
A repeating arrangement of atoms in a solid. Lattices are highly ordered structures held together by bonds between atoms.
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metal
A shiny, malleable element that conducts heat and electricity. Metals include magnesium and calcium. They tend to form cations by losing valence electrons.
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molecule
A group of atoms bonded together. An oxygen gas molecule is made up of two oxygen atoms bonded together.
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neutral atom
An atom with no net charge. An atom is neutral when it has an equal number of protons and electrons.
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noble gas
An element that is non-reactive due to its full valence shell. The noble gases have full valence shells so they don't tend to form chemical bonds with other atoms.
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non-metal
A dull, brittle element that does not conduct heat or electricity. Non-metals include sulfur and oxygen. They tend to form anions by gaining valence electrons.
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periodic table
A grid arrangement of all known elements in order of atomic number. The modern periodic table was developed by Dmitri Mendeleev in the 1860s.
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valence shell
The outermost occupied shell of an atom. Atoms form bonds to obtain full valence shells. They can do this by transferring or sharing electrons.
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isotopes
Same element that has the same atomic number (same number of protons) but a different mass number (number of neutrons). E.g., Carbon 12 (12 \= mass number and 6 \= protons) Carbon 13 (13 \= mass number and 6 \= protons)
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Metallic structure
Metallic bonds are strong, so metals can maintain a regular structure and usually have high melting and boiling points.
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Ionic bond
The two atoms are attracted to each other due to opposite charges
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What do ionic compounds have in common?
•Made of positive and negative ions
•Usually solid at room temperature
•High melting points because ionic bonds are very strong
•Dissolve in water to form aqueous solutions. Aqueous solutions conduct electricity
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Covalent bond
Non-metals share electrons to form covalent bonds
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Covalent Compound Properties
•Exist as gas, liquids or solids with low melting points as covalent bonds are weak
•Generally don't conduct electricity because they aren't made of ions
•Usually don't dissolve in water
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Metallic bonding
Occurs when a group of metal atoms shares a cloud of valence electrons sea of free floating valence electrons not attached to any one atom are free to move
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Metallic bonding properties
malleable, ductile, good conductor of heat and electrons
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element
Elements are pure substances that are composed of only one type of atom. There are over 100 discovered
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compound
Compounds are substances that are formed by two or more different types of elements that are chemically bonded
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To name simple compounds of metals and non-metals:
Write down the name of the metal.Write down the name of the non-metal, changing the ending of the word to "-ide".
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What is the name of the compound made when the following elements combine? magnesium and oxygensodium and chlorineoxygen and iron
magnesium oxidesodium chlorideiron oxide
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Naming compounds containing oxygen
For compounds containing two elements plus oxygen, the ending of the other non-metal usually changes to "-ate".
e.g. nickel + sulfur + oxygen = nickel sulfate
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ion
An atom with a charge
If an atom loses an electron, it becomes positively charged. If an atom gains an electron, it becomes negatively charged.
Cation: positive charge
Anion: negative charge
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collision theory
Particles must collide with enough energy and correct orientation in order to react
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unsuccessful collision
reactant particles approach each otherthey collide with the incorrect orientationreactant particles separate
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successful collision
reactant particles approach each otherthey collide with the correct orientationproducts formed
higher temp means particles collide more as they move more
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surface area
more places for successful collisions
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Catalysts/enzymes
proteins that help making/ breaking bonds therefore speeding up reactions. (without enzymes life wouldn't exist)
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Biological Catalysts are proteins that:
* Lower the activation energy * Speed up rate of reaction * Don't get used up in the reaction
e.g. Amylase breaks down carbohydrates into glucose
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rate of reaction
How quickly the reactants react to form the product
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rate of reaction (formula)
amount of reactant used or product formed / time
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when do reactions occur
Reactions happen when particles (the reactants) collide with enough energy to become chemically joined
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Precipitation Reactions
When two solutions containing soluble salts produce an insoluble solid called a "precipitate".
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precipitate
A solid that forms from a solution during a chemical reaction.
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Precipitation
a reaction between two solutions that forms an insoluble solid
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Corrosion
Wearing away of a metal (Rust) Air, water and chemicals in air and water can be corrosive (eg. salt water)
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Combustion
When a substance reacts with oxygen to form carbon dioxide and water. A compound containing carbon and hydrogen (and sometimes oxygen) combines with oxygen gas to produce carbon dioxide and water. e.g. hydrocarbon + oxygen -\> carbon dioxide + water + heat and light CxHy(Oz) + O -\> CO2 +H2O
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oxidation-reduction/redox reaction
reaction that involves the transfer of electrons between atoms