What does this mean??? Atomic mass symbol Atomic #

How do we define an element? All elements have a symbol, atomic number and an atomic mass The symbol is a shorthand way of writing the name The atomic number places the element on the Periodic Table

Atomic Number = # of protons in an atom How can we determine the atomic number of an atom? Atomic Number = # of protons in an atom # Protons ALWAYS = # Electrons!

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How can we calculate the total atomic mass of an atom? Protons + Neutrons = Atomic Mass of an atom

Where do we find electrons in an atom? Electrons are found orbiting or circling the nucleus in regions called electron clouds.

So….Why do you think the number of protons always equals the number of electrons? Because it helps keep the atom __________

Decoding the P.T. The atomic number is also equal to the total number of protons The total number of electrons is always equal to the number of protons The atomic mass is the number of protons plus the number of neutrons

How is matter found? Matter can be found three ways: Single Elements Compounds Mixtures 10

A compound is two or more elements chemically combined A compound is two or more elements chemically combined. It is the SAME THROUGHOUT! A mixture is two or more different substances physically placed together. It can be physically taken apart!

Compound facts! Compounds have a single formula NaCl = Sodium Chloride = Salt!!!! Compounds cannot be separated physically You cannot take the Na away from the Cl with your hands!!!!! The number below (subscript) an element in the formula is the number of atoms of that element H2O = 2 atoms of H and 1 atom of O 12

What is a mixture? A mixture is two or more substances physically combined The substances will keep their own properties 13

Two types of mixtures What could you be drinking that would be the same color throughout and taste the same every time you take a sip?? Homogeneous: the mixture is the same throughout. (Though not mixtures, elements and compounds are also homogeneous) Heterogeneous: the mixture varies from one portion to another 14

What’s the solution? A solution is the same throughout It is formed when a soluble (solid, liquid or gas) substance dissolves into another A solution is transparent which means you can see through it If a substance does NOT dissolve it is said to be insoluble 15

What are the two parts? The two parts of a solution are the solute and solvent The solute is the substance being dissolved or the substance that disappears The solvent is the substance that dissolves the solute. 16