Particles of Matter

Atoms and Molecules The smallest particle of all matter and the basis of everything in the Universe – Atom.

Inside an Atom Atoms are composed of 3 basic parts: Protons – positively (+) charged particles located in the nucleus of the atom. Neutrons – neutrally (O) charged particles located in the nucleus of the atom. Electrons – negatively (-) charged particles located in the orbits surrounding the nucleus.

Orbits Shell Basics: The orbits, shells, surround the nucleus and hold a specific number of electrons that are always moving. Shells are sometimes called energy levels

Energy Levels Orbit 1 (K) – 2 electrons Orbit 2 (L) – 8 electrons Orbit 3 (M) – 8 electrons Orbit 4 (N) – 18 electrons 10 18 36

Scientists Behind Atoms Democritus Greek philosopher Lived about 440 B.C. He thought that there were smallest possible “pieces” of everything. Called this smallest piece, atomos – Greek for “uncuttable”.

Scientists Behind Atoms 2. Dalton British schoolteacher – 1802 Proposed the atomic theory Theory about atoms Dalton’s ideas form the basis of our understanding of atoms!

Dalton’s Conclusion about Atoms Through experiments he concluded: Atoms can’t be broken into smaller pieces. All atoms in an element are exactly alike. Atoms of different elements are different. Atoms of two or more elements combine to form compounds. Atoms of each element have a unique mass. The masses of the elements in a compound are always in a constant ratio.

Organizing Elements Dmitri Mendeleev 1800’s, Russian scientist Thought elements could be organized by: Similar chemical and physical properties Atomic mass Bonding power

The First Periodic Table 1869, Mendeleev published the first periodic table of elements. Periodic = “a regular, repeating pattern”

Organizing the Periodic Table Arranged by atomic number Groups (families): Vertical columns down, 1-18. Based on similar characteristics Periods : horizontal rows across, 1-7. Metals Classified based on physical properties such as: Hardness Shininess Malleability – can be pounded into shape Ductility – can be pulled or drawn into a long wire Good conductors – transmit heat and electricity easily. Solid at room temperature.

Organizing the Periodic Table Nonmetals Characteristics are opposite of metals: Gas at room temperature. Poor conductors Dull Brittle – break easily Metalloids Boarder between metals and nonmetals Characteristics similar to both metals and nonmetals: Varying ability to conduct electricity. Temperature, light or impurities affect conductivity. 7. Nobel Gases Group 18 Chemically stable and unreactive Outer shell, valance electrons, is completely full – can’t form compounds

The Periodic Table 1 18 Groups 1 2 13 14 15 16 17 2 3 3 4 5 6 7 8 9 10 Key: Metal Metalloid Nonmetal Nobel Gas The Periodic Table 1 18 Groups 1 2 13 14 15 16 17 2 3 3 4 5 6 7 8 9 10 11 12 Periods 4 5 6 7

Inside the Squares Each square contains: Element Name Element Symbol Atomic Number Number of protons in the nucleus or electrons in the orbits of the atom (p = e-) Atomic Mass The number of protons + neutrons in the nucleus of the atom (p + n)

Atomic Number & Atomic Mass All atoms have a specific mass that is calculated by the number of Protons and Neutrons in the nucleus of the atom. Atomic Mass = Protons + Neutrons (p + n) The atomic number is calculated by the number of protons in the nucleus or the number of electrons in the orbits. Atomic Number = Protons or electrons (p = e-) Electrically Neutral!

Protons, Neutrons & Electrons Atomic Number = Protons (p = e-) Atomic Mass = Protons + Neutrons (p + n) (p=e-) (p+n) (p) (n) (e-) Atomic Mass Atomic Number Element Symbol Element Name Element Symbol Atomic Number Atomic Mass Protons Neutrons Electrons + Carbon C 6 12 6 6 6

Protons, Neutrons & Electrons (p=e-) (p+n) (p) (n) (e-) Element Symbol Atomic Number Atomic Mass Protons Neutrons Electrons Helium He 4 7 14 11 Iron Fe 56 30 Copper 29 Ag 108 61 2 2 + 2 2 Nitrogen N 7 7 23 11 12 11 Sodium Na 26 26 26 Cu 64 35 29 47 Silver 47 47

Atomic Structure Nitrogen: Oxygen: 7 8 7 8 7 14 8 16 7 8 7 8 7 8 Atomic Number: ________ Protons: _____ Neutrons: _____ Electrons: _____ Oxygen: Atomic Number: ________ Protons: _____ Neutrons: _____ Electrons: _____ 7 8 7 8 7 Atomic Mass: 14 8 Atomic Mass: 16 7 8 p = n = 7 p = n = 8 7 8

Atomic Structure Sodium: Hydrogen: Atomic Number: ________ Protons: _____ Neutrons: _____ Electrons: _____ Hydrogen: Atomic Number: ________ Protons: _____ Neutrons: _____ Electrons: _____ 11 1 11 12 Atomic Mass: 23 1 1 11 Atomic Mass: 1 p = n = 1 p = n = 11 12