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Chemistry Concept Map - Coggle Diagram
Chemistry Concept Map
Calculations
Empirical formula
The simplest ratio in which a molecular formula can be expressed. It is calculated by dividing either the percentage or the mass of each element in the formula by it's mass number and then dividing the results by the smallest result.
Yields
Theoretical yield
The maximum possible mass of product that can be achieved through a chemical reaction under optimum conditions.
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Percentage yield
(Actual yield/Theoretical yield) x 100. Used to find the percentage of the theoretical yield the actual yield comprises.
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The Periodic Table
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To read information about specific elements on the periodic table you can look at the individual cells of the table. The number at the top will usually be the atomic number, the number at the bottom will usually be the mass number, and the chemical symbol is in the middle. Often times, the letters of the chemical symbol won't match up to the element and this is because the symbols can be based on the element's latin name instead of their English name.
Periods and Groups
Period: The rows of the periodic table The period number indicates the number of electron shells in the atomic structure. Elements in periods are arranged in increasing atomic number.
Group: The columns of the periodic table. Elements in a group share chemical properties. The group number shows the number of valence electrons (electrons in the outermost energy level).
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Group 1
Group 1 consists of Alkali Metals. Their properties are high thermal and electrical conductivity, lustre, ductility and malleability which are also general qualities of metals. They have one valence electron.
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Group 7
Group 7 consists of halogens. They are non-metals have very low melting and boiling points and have 7 valence electrons.
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Group 0
Group 0 consists of noble gases. They are non-metals that are entirely inert due to their full outer shell which means they can not react/bond with other elements.
Electronic configuration
The first electron shell of an atom can hold 2 electrons. Every other shell can hold up to 8 electrons. The outermost shell holds electrons equivalent to the group number. Every other shell is full. For example, Lithium is the first element in Group 1 and is in period 2, so it's electronic configuration is 2.1. Potassium is the third element in Group 1 and is in period 4 so it's electronic configuration is 2.8.8.1.
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Reactivity series
Group 1 reactivity increases as you go down the group since the atomic radius increases with the ascending number of electron shells. The further down the group you go, the weaker the electrostatic force of attraction between the nucleus and the valence is which allows it to be lost more easily. Group 7 reactivity decreases as you go down the group since the atomic radius decreases with the ascending number of electron shells. The further down the group you go, the weaker the electrostatic force of attraction between the nucleus and the valence is which stops it from gaining electrons as easily.
Atomic Structure
Structure
The structure of an atom consists of three distinct particles. The electron, the proton, and the neutron. There are the same number of protons and electrons in an atom but a different number of neutrons. Protons and neutrons are in the nucleus. Atoms also have a certain number of electron shells where electrons orbit the nucleus. Their number depends on their period in the periodic table and this affects the atomic radius.
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Isotopes
Isotopes are variants of an atom that have a different number of neutrons but the same number of protons which results in a different relative atomic mass but the same chemical properties.
Relative Atomic Mass
Relative atomic mass is the mean mass of all the isotopes of an element. Since it is an average some elements do not have an integer for their relative atomic mass.
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Bonds
Ionic Bonds
An ionic bond is a bond between a metal and a non-metal where the metal loses valence electrons and the non-metal gains them to have a full outer shell. Since the metal now has a net positive charge due to the loss of electrons and the non-metal has a net negative charge due to the gain of electrons, the two atoms are electrostatically attracted.
Ions form an ionic lattice which is a regular repeating structure alternating between the positive and negative ions in a lattice configuration. The lattice is formed because ions attract each other and form a pattern with oppositely charged ions next top each other.
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Covalent Bonds
A covalent bond is a bond between two non-metals where valence electrons are shared so that they can both achieve a full outer shell and consequently, noble gas configuration. The positive nuclei and negative electrons of both atoms are intermolecuiarly attracted. There may be a different number of each atom depending on how many are needed to create full outer shells.
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Metallic Bonds
A metallic bond is the bond between metals in a pure substance or alloy consisting of only metals. The valence electrons delocalise and create the sea of electrons which causes the positively charged ions to electrostatically attract to the negative electrons, essentially functioning as a type of "glue".
Element structures
Covalent structures
Simple covalent compound
A molecule made up of only a few atoms that are covalently bonded. Several of these compounds make up a substance.
Giant covalent structure
A giant structure of 2 or more non-metal atoms covalently bonded together. It is a three dimensional repeating structure that goes on for a very large amount of atoms.
Allotropes
Allotropes are different physical configurations in which elements can exist that display different properties depending on their physical forms. For example, carbon can be graphite or a diamond. The graphite structure allows the layers to slide over each other which makes it a slippery material perfect for writing with, whereas the diamond structure makes it very hard and ideal for industrial equipment such as drills.
