what did you learn? I learned that valence electrons have the most potential energy. Also that the number of electrons can change without changing the element. what did you still have questions about? I still had questions about whether or not an element is changed when adding or subtracting electrons. |
What I knew
AtomsAtoms are the basic building blocks of matter. They contain a nucleus and an electron cloud. In the nucleus are the protons and neutrons. In the electron cloud there are the electrons. All atoms are placed on a table. This table is called the Periodic Table of Elements. They are placed in numerical order by their atomic number. Atomic numbers are determined by the number of protons. On the periodic table there are rows and columns. The rows are called periods and columns are groups. What row an element is in tells you the number of energy levels it has. The group number tells you the number of valence electrons and re-activity levels. All atoms are classified as metals, non-metals, and metalloids. On the left side of the table are the metals, then the metalloids and lastly the non-metals.
Chemical EquationsChemical equations are a compound of elements that express a chemical reaction. Im each equation there are reactants, which are located on the left side and products which are located on the right. In between the products and reactants is a yield sign. The yield sign means equal to. According to the Law of Conservation of Mass, each equation must be balanced, meaning the elements on both sides but be the same. So if your reactant has 4 hydrogen so must your product. They don't have to be with the same element in the products but there has to be the same amount. If the equation is not balanced then in order to balance it you have to add coefficients to the compounds on either side of the yield sign.
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Protons, Neutrons, and ElectronsProtons, Neutrons, and Electrons are all atomic particles that make up the atom. The Proton is a positively charged atomic particle located in the nucleus. It determines the identity of the atom and always stays the same. Electrons on the other hand are outside the nucleus in the Electron Cloud. Electrons are negatively charged and don't always determine the identity of the element. Atoms can lose or gain electrons. In the electron cloud there are energy levels. Each level has different amounts of electrons that can fit in it. The outer most shell the atom has determines its reactivity. If the outer level is full then the element is non-reactive. If there are 7 or 1 electrons they are highly reactive. Others reactivity depends on the number of electrons.
Chemical ReactionsA chemical reaction is what happens when two chemicals react to each other with touched together. In order to know a chemical reaction has occurred a new substance has to be formed. Ways to tell if a new substance has been formed you can look for these signs. There can be a color change, a different smell, a precipitate could form, a gas or bubbles could be released, and finally a temperature change. In order to remember each reaction just remember "Please excuse burps, coughs, and sneezes." There are two types of chemical reactions. One that releases energy while one requires energy. The one that requires energy is called endothermic. One that releases energy is exothermic.
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