Introduction to atomic Particles Inside the Atom

The Atoms Family https://www.youtube.com/watch?v=Le9a8C0Pk2c

THE ATOM The atom is a particle in an element The atom is composed of smaller particles called “sub-atomic particles” Subatomic particle Where is it found in the atom? Charge ( + / - / 0) Protons Nucleus + Neutrons Electrons Shells -

1) Structure of the atom: nucleus Neutrons (0 charge) – have mass Protons (+ charge) – have mass Electron shell Electrons (- charge) have almost no mass Electron Shells: - 1% of atom’s mass - 99% of atom’s volume Nucleus: - 99% of atom’s mass - 1% of atom’s volume

Chemical Symbols A chemical symbol is an abbreviation of the name of an element Chemical symbols always have one or two letters The first letter is ALWAYS a capital If there is more than one letter, the second letter is a small letter

H – hydrogen F - fluorine O – oxygen C - carbon N – nitrogen B - boron Cl – chlorine He - helium Ca – calcium Li - lithium

Chemical Formula A chemical formula is the combination of symbols that represents a particular compound. It indicates which elements are present and in what proportion NaCl – Sodium Chloride O2 – oxygen gas

Getting info from the Periodic Table The periodic table has loads of information on it that you need to be able to find. Most importantly atomic number, mass number, element symbol, and element name.

Atomic Number – the number of protons and electrons found in a neutral atom 4 Be Beryllium 9.0 Atomic Mass – the average mass of an atom (Protons + Neutrons)

. The atomic number indicates the number of protons (or electrons) in that atom The mass number represents the sum of protons and neutrons in that atom Neutrons = mass # - atomic #

Determining number particles Protons = atomic number Electrons = atomic number Neutrons = mass number – atomic number

Example: Sodium Atomic number = 11 Mass number = 23 Number of neutrons = 23 – 11 = 12 Note: the number of neutrons is either equal to or greater than the number of protons

Standard Atomic Notation 1. Write the symbol of the element 2. Write the mass number at the top left 3. Write the atomic number at the bottom left Ex Magnesium Ex Lithium 24 7 Li Mg 3 12

Standard notation Example: Chlorine

Atoms and Shell Diagram Puzzle Symbol element Atomic number Atomic mass # p # e # n 24 Mg 12 Magnesium 24-12=12 34 K 19 Potassium 34 19 19 34-19=15 19 Sodium 11 28 11 11 17 Chlorine

EXAMPLES Name Symbol Atomic # Atomic Mass #p #e #n Zinc Zn 30 65 35 19 10 Ca N 28

Check it out! Overflowing fountains… Look for patterns… http://www.colorado.edu/physics/2000/applets/a2.html www.explorelearning.com Element builder

Drawing Bohr-R diagrams Label # of p+ and n in the nucleus Start filling electron energy levels (shells) from the nucleus 1st level – Maximum 2 electrons 2nd level – Maximum 8 electrons 3rd level – Maximum 8 electrons

Ex. Fluorine 19 F 9 Protons: same as atomic number = 9 Neutrons: mass number – atomic number = 19 – 9 = 10 Electrons: same as atomic number = 9

Ex. Magnesium – S.A.N. and Bohr Rutherford 12p+ 12 n 24 Mg 12 Protons: same as atomic number = 12 Neutrons: mass number – atomic number = 24 – 12 = 12 Electrons: same as atomic number = 12

Homework Page 89 #1-2 Page 93 #1-8