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The Atom and Periodic Table

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1 The Atom and Periodic Table
Physical Science

2 Element verse Atom ATOM ELEMENT Smallest particle of an element
A substance that cannot be broken down into simpler substances Ex: Neon, Gold, Helium ATOM Smallest particle of an element Counting unit of elements

3 History of the Atomic Model
Democritus --believed in the atom J.J. Thomson --found the electron John Dalton --made the theory on atoms Ernest Rutherford --found the nucleus

4 History of the Atomic Model
Neil Bohr --established energy levels Electron Cloud Model --the current model of the atom

5 3 Subatomic Particles Atoms can be broken into:
Electrons Negatively charged Symbol = e- Extremely small mass Protons Positively charged Symbol = p+ Mass = 1 Neutrons No charged (neutral) Symbol = n Mass = 1

6 Parts of an Atom Nucleus Energy Levels/Shells/Orbitals
Center of the atom Small, dense, positively charged Where Protons and Neutrons remain Energy Levels/Shells/Orbitals Around the nucleus Contains the electrons

7 Atomic Number The Identify of the element Number of Protons
Top of the Element Block SECRET: Also the number of electrons

8 Mass Number The sum of the Protons and Neutrons
Bottom Number of the element block Round to the Nearest Whole Number

9 Understanding an Element Block
ATOMIC NUMBER 10 Ne Element Symbol 1st letter is upper case 2nd letter is lower case NEON Element Name 20.18 Mass NUMBER

10 How do you Find Items Number of Protons = Atomic Number
Number of Electrons = Number of Protons (Because Atoms are neutral which means positive equals negative) Number of Neutrons = Mass Number subtract Atomic Number

11 Electron, Protons, Neutrons Example Practice
Name Symbol Atomic Number Mass Number Number of Protons Number of Electrons Number of Neutrons NEON BORON

12 End Day ONE

13 ISOTOPES Atoms of the same element that have the same atomic number but different mass numbers # of protons stays the same # of neutrons change

14 How Isotopes are Written
Elements name/symbol dash mass number Ex: Oxygen— p+= n = Oxygen— p+= n = O— p+= n =

15 Why is Mass Number a Decimal?
Mass Number is the weighted average of all the isotopes of an atom The isotope whom mass number is closest to the actual mass number is more abundant

16 IONS Charged Particles Negative Charge = gains electrons
Positive Charge = lose electrons

17 End Day TWO

18 The Periodic Table An arrangement of elements in columns based on properties that repeat from row to row Modern Periodic Table arranged by Henry Moseley Arranged by increasing atomic number

19 Parts of the Periodic Table
ROWS Called Periods Go across COLUMNS Called Groups Go up and down

20 Periods 7 periods Elements in the same period have:
Same number of energy levels or shells or orbitals

21 Groups 18 groups Elements in the same group have the same: Properties
Valence Electrons Oxidation Numbers

22 Valence Electrons Code:
Number of electrons on the outermost (last) energy level Code: 1, 2, 3, 4, 5, 6, 7, 8 Number next to “A” at the top of the column

23 Know Your Roman Numerals
I = 1 II = 2 III = 3 IV = 4 V = 5 VI = 6 VII = 7 VIII = 8

24 Oxidation Number Number of electrons an atom will gain or lose to become stable Stable = 8 electrons on last shell Code: +1, +2, +3, ±4, -3, -2, -1, 0 “+” means lose electrons “—” means gain electrons

25 Labeling the Periodic Table

26 End Day Three

27 Bohr’s Model Focuses On Electrons Places electrons into energy levels
Developed by Neil Bohr

28 Components of Bohr’s Model
Circles DOTS Number of Circles = Period Number = Number of Energy Level Go on the Last Circle Number of Dots = Number of Valence Electrons Important Note First energy level has a max of 2 electrons All other energy levels have a max of 8 electrons

29 Steps to Draw Bohr’s Model
Place a dot to be Nucleus Place circles around Nucleus Place dots on last circle in correct order EXAMPLE Oxygen

30 Bohr Model Practice NEON Boron Helium

31 Electron Dot Diagrams Model of an atom in which each dot represents the valence electrons AKA: Lewis Dot Diagrams

32 Steps to Draw Dot Diagrams
Identify the number of valence electrons Write the element’s symbol Place dots around the symbol equal to valence electrons in correct order Example NEON

33 Dot Diagram Practice Fluorine Sodium Carbon

34 End Day Four

35 Classifying Elements Elements are classified as metals, nonmetals, or metalloids based on properties and location on the periodic table

36 Metals Most elements are them Malleable: hammer into sheets
Good Conductors of electricity/heat Solid at room temperature (except Mercury) Ductile: turn into thin wire Luster: reflect light Malleable: hammer into sheets High Melting Point Left side of the stair step Francium: Most reactive metal High Boiling Point

37 Nonmetals Dull Brittle Poor Conductors of electricity/heat
Most are gas at room temperature Low Melting Point Low Boiling Point Right Side of Stair Step Fluorine: most reactive nonmetal

38 Metalloids Have BOTH characteristics of metals and nonmetals
Found on the stair-step line What are the Metalloids B, Si, Ge, As, Sb, Te, Po, At

39 Periodic Trend Reactivity
As you go left to right across a period, the less reactive elements become

40 End Day Five

41 THE FAMILIES AND GROUPS OF THE PERIODIC TABLE

42 Alkali Metals Group IA 1 valence electron
Reactivity increases from top to bottom Francium is most reactive metal

43 Alkaline Earth Metals Group IIA 2 valence electrons
Ca: is in your bones, teeth, shells

44 Transitional Metals THE MIDDLE OF THE PERIODIC TABLE Groups 3B-12B
Vary in oxidation numbers Brightly colored Likes to combine with Oxygen

45 BORON FAMILY Group IIIA 3 valence electrons
Al: most abundant metal in Earth’s crust

46 Carbon Family Group IVA 4 valence electrons
Carbon is the element of life

47 Nitrogen Family Group VA 5 valence electrons N is 78% of air
Main component of fertilizer

48 Oxygen Family Group VIA 6 valence electrons
O: most abundant element in Earth’s crust

49 The Halogens Group VIIA 7 valence electrons Salt formers
Reactive with metals Fluorine: most reactive nonmetal

50 Noble Gases Group VIIIA 8 valence electrons Stable = not reactive
Inert Gases All Shells are full

51 End UNIT


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