I’ve gotta ask….. Are You…… Thirsty for Chemistry?

Color Change Demonstration Get a beaker…… No, not that Beaker.

Color Change Demonstration “Water” Water + Baking Soda “Fruit Punch” Phenolphthalein (Think CSI) “Milk” Barium Chloride Color Change Demonstration Dichromate + Hydrochloric acid These are toxic, you cannot drink them!!

An Intro to Elements and the Periodic Table It’s All in the Atom An Intro to Elements and the Periodic Table

Elements Robert Boyle (1627-1691) gave the basis for modern definition of an element “An element is a pure substance that cannot be chemically broken down into a simpler substance. Every element has it’s own atomic structure, which we call an atom

Parts of an Atom An atom is made up of 3 types of particles. 1) The electron (e-) Has a charge of -1 Has relatively no mass Is found in an orbital/shell, around the nucleus of an atom

Parts of an Atom 2) The proton (p+) Has a charge of +1 Has a mass of 1 amu Amu = Atomic Mass Unit Is found in the nucleus of the atom

Parts of an Atom 3) the neutron (n) Has NO charge Has a mass of 1 amu Is found in the nucleus of the atom

Bohr Diagram of the Atom Niels Bohr was a Danish physicist. He proposed a model of an atom where: protons and neutrons are located in the centre of the atom (nucleus) and the electrons move around the nucleus in orbits called shells

Bohr Diagrams Each shell can hold a specific number of electrons. K-shell is the first shell and can hold 2 electrons L-shell is the second shell and can hold 8 electrons M-shell is the third shell and can hold 8 electrons Remember: Neutral atoms always have the same number of electrons as protons (charges cancel)

Bohr Diagrams E.g-a boron atom has 5 p+, 5 e-, and 6 n. Draw the Bohr diagram: + + + + +

Bohr Diagrams A beryillium atom has 4 p+, 4 e-, and 5n. Draw it: + + +

Bohr Diagram A phosphorus atom has 15 p+, 15 e-, and 16 n. Draw it:

Reading from the Periodic Table Each element in the periodic table is represented by a symbol. Every symbol has an upper case letter. Some symbols have two letters. The first is upper case The second is lower case (e.g. Ca is calcium)

E.g. C is the symbol for carbon Cl is the symbol for chlorine Cu is the symbol for copper

Atomic Number Is the number of protons that an atom has. Each element has a unique atomic number. Every element is arranged according to atomic number on the periodic table. Atomic number = # of p+

Atomic Number Is found in the top left-hand corner

Atomic Mass Is the mass of the atom in amu. Since each proton has a mass of 1 amu, and each neutron has a mass of 1 amu, then the atomic mass is equal to the number of protons and neutrons. Atomic mass = # protons + # neutrons

Atomic Mass E.g. Nitrogen has 7 p+ and 7 n. So, atomic mass = 7 + 7 = 14 amu Is found under the symbol.

On Your Periodic Table

Assignment Use your periodic table to fill in the table on page 4. We’ll do a few together.

Symbol Name Atomic # Atomic mass P+ e- n Li Lithium 3 7 4 O Oxygen 8 16 P Phosphorus 15 31 F Flourine 9 19 10 Br bromine 35 80 45 Fe iron 26 56 30 K potassium 39 20 Bi bismuth 83 210 127 Pb lead 82 207 125