Atomic Structure, Periodic Table, and Elements

1. Chapter 5“Atomic Structure and the Periodic Table”

2. BellRinger-12/3/08 • What is an atom? • What is an element? • How are elements named? • What is the most abundant element in the universe?

3. Atomic Structure Atoms are made of three sub-atomic particles: 1._____________ 2._____________ 3._____________ protons neutrons electrons

4. This central part is called the ___________. • The central part of the atom contains the • _________ and _________. • Protons have a ___________charge. • Neutrons have ________ charge. nucleus protons neutrons positive no positive • The nucleus has an overall ________ charge. • The strong __________ __________ holds • protons and neutrons together in the nucleus. nuclear force

5. Electrons (e-) are moving around an area • called the ________ ______. electron cloud negative • Electrons have a _________ charge. • The electron cloud has a _________charge. negative The e- cloud is usually 10,000 times larger than the nucleus. HOWEVER…

6. protons and neutrons weigh about 0.00000000000000000000000167 g • electrons weigh about 0.00000000000000000000000000091 g To you and me, protons/neutrons are about 2000 times HEAVIER than electrons!!!!!

7. The Periodic Table A table that shows a periodic or repeating pattern of properties of the elements

8. History of the Periodic Table • Russian chemist, Dmitri Mendeleev, produced the first periodic table in 1869 • Elements with similar properties were arranged in rows in order of increasing atomic mass.

9. The Modern Periodic Table • Includes over 100 elements that make • up everything we see and touch • Elements with similar properties • are found in columns. • Arranged by increasing atomic number • Three types of elements: metals, nonmetals, • and metalloids

10. Reading the Periodic Table Each square on the periodic table gives particular information about the element. 50 Sn Tin 118.71 Atomic Number -------- Chemical Symbol -------- Element Name --------- Atomic mass ---

11. Atomic Number - the number of protons in an element; In a neutral atom, the number of electrons is equal to the number of protons. Atomic Mass - the average mass of all the isotopes of an element. Chemical Symbol- an abbreviation of the element’s name. It contains one or two letters. First letter is always capitalized.

12. Atomic Mass Number – The total number of protons and neutrons in the nucleus of an atom. Round the atomic mass to the nearest whole number. The number of neutrons equals atomic mass number minus atomic number.

13. Isotopes - elements with the same number of protons, but DIFFERENT numbers of neutrons. • Examples include chlorine-37, • chlorine-35, carbon-14

14. Period - • A horizontal row on the periodic • table. • The periodic table has 7 periods. • The period number tells us how • many energy levels an atom has.

15. Group- • A vertical column on the periodic table. • Also called a family of elements • Elements share similar physical and • chemical properties. • The family number tell us how many • electrons an atom has in its outermost • energy level or shell (valence electrons).

16. Family Names 1. Alkali metals 2. Alkaline earth metals 3-12. Transition elements 13 (3). Boron family Rare Earth Elements - Lanthanides Actinides 14 (3). Carbon family 15 (5). Nitrogen family 16 (6). Oxygen family 17 (7). Halogen family 18 (8). Noble gases

17. 8 O15.9994 This element’s atomic number is 8. How many protons does it have? ___ 8 If its atomic mass number were 14, how many neutrons would it have? 8 protons + _?_ neutrons = 14 atomic mass number Also remember, atomic mass number minus atomic number equals number of neutrons. 6 neutrons

18. 79 Au197.0 How many protons does gold have? ___ 79 If its atomic mass number were 197, how many neutrons would it have? 79 protons + __ neutrons = 197 mass number 118 neutrons

19. Element Name Chemical Symbol Atomic Number Atomic Mass Number Number of Protons Number of Neutrons Number of Electrons Helium 2 4 Mg 12 12 Try this: