Maybe I should be wearing goggles CHEMISTRY Chemistry Pre-Test 1. What is matter? 2. Name the particles of the atom 3. List the CHARGES of each particle 4. How do we determine the Atomic Number of an element? 5. How do we determine the Atomic Mass of an element? 6. Name at least five (5) elements and their symbols What is Matter? • • • • Anything that can be smelled, tasted, touched… Has mass and volume (takes up space) Matter exists in a state or phase Phases of matter include solid, liquid, gas, nonNewtonian, & plasma Common Phases of Matter: Solid, Liquid, Gas Non-Newtonian substances sometimes behave like a solid and sometimes like a liquid Plasmas consist of freely moving charged particles, (electrons & ions) It is perhaps the most common phase of matter in the universe Matter is made up of atoms… What’s an Atom? • The word ATOM (átomos) was first used by the Greek philosopher Democritus • Atom translates to “Indivisible” • It is the smallest particle characterizing an element • We can’t see the parts of atoms, even with modern technology, so we have an Atomic Theory • A theory is a good, logical idea about something but it hasn’t been proven to be true Democritus 460-370 BCE Atomic Theory It’s thought that atoms are made of these common particles: • PROTON- has a positive Charge (P+) • NEUTRON- has a neutral charge; has both positive and negative attributes (N=) • ELECTRON- has a negative charge (e-) Atomic Structure Proton Nucleus Neutron electron Electron Clouds Benfey’s Periodic Table 1960 Stowe Periodic Table 1988 Mayan Periodic Table 2001 Spiral Periodic Table 2005 Dufour Periodic Table There is no single periodic table… Most Common Periodic Table • First organized using the known properties from other chemists like Stanislao Cannizzaro • Dmitri Mendeleev created the most commonly used table of elements in 1869 Mendeleev’s table 1869 Most Commonly Used Table Period of elements • Organized horizontally • Indicates # of electron levels Family of elements • Organized vertically • Indicates # of electrons in outer cloud Elemental Symbol (Often from Latin or Greek) (1st letter is upper case, 2nd is lower case) Nitrogen # of e- in each electron cloud 2 5 7 N 14.0067 Elemental Name Atomic Number (# of P+) Atomic Mass (# of P+ & N=) Q: How can I calculate the number of neutrons in an element?? Elemental Names & Symbols • • • • • • Fe Iron; Latin Ferrum meaning “firm” Cu Copper; Greek for island of Cypress/ Cuprius Na Sodium; Natrium (Latin) meaning “soda”/ “salt” • Ag • Silver; from Latin Argentum meaning “bright” More Elemental Names & Symbols • Au • Gold; (Latin) Aurum- Roman Goddess of dawn • Hg • Mercury; Greek Hydragyrium meaning ‘liquid silver’ • Pb • Lead; Latin for Plumbum; origin of ‘plumber’ Element song? http://www.privatehand.com/flash/elements.html John Dalton September 6, 1766 – July 27, 1844 • All matter is made of atoms • Atoms of an element are identical • Atoms are rearranged in reactions Elements are individual atoms… • When elements join together a compound forms • Elements join forming molecules of a compound • There several ways for molecules to form… Covalent Bonding • Atoms join together to form molecules of a compound through bonding • Atoms “prefer” to have 8 e- in the outer cloud • In order to become more stable, elements will share e• Water (H2O) is an example of covalent bonding H H O Ionic Bonding • Occurs with salts • One element gives up an electron while another gains an electron • In the case of Sodium Chloride, Na gives up an electron and Cl gains one • This creates ions: the Na atom has a positive charge & the Cl atom has a negative charge • Opposite charges attract and a compound is formed Na Cl