1 VALENCE SHELL OUTERMOST ENERGY LEVEL CONTAINING ELECTRONS IN THE GROUND STATE

2 VALENCE ELECTRONS ELECTRONS IN VALENCE SHELL DETERMINE MOST CHEMICAL PROPERTIES (VERY IMPORTANT)

3 VALENCE ELECTRON EFFECTS ELEMENTS WITH THE SAME NUMBER OF VALENCE ELECTRONS TEND TO REACT SIMILARLY GROUP VIII ELEMENTS HAVE COMPLETE VALENCE SHELLS SO DON’T REACT

4 PERIODIC TABLE ARRANGED FROM LOWEST TO HIGHEST ATOMIC NUMBER PERIOD = HORIZONTAL ROW ELEMENTS IN PERIODS HAVE SAME VALENCE SHELL FAMILY OR GROUP = VERTICAL COLUMN

5 PERIODIC TABLE II ELEMENTS IN GROUP HAVE THE SAME NUMBER OF VALENCE ELECTRONS GROUPS CORRELATE TO SUBLEVELS

6 ELECTRON DOT SYMBOLS ALSO CALLED LEWIS DOT SYMBOLS DOT SYMBOLS SHOW ONLY VALENCE ELECTRONS

7 DOT SYMBOL RULES SHOW ELEMENT SYMBOL USE 4 SIDES: TOP, RIGHT, BOTTOM, LEFT ONLY 2 DOTS PER SIDE 1 ST DOT GOES ON ANY SIDE

8 DOT SYMBOLS RULES II 2 ND DOT PAIRS WITH 1 ST REMAINING DOTS ARRANGED 1 PER SIDE UNTIL YOU HAVE TO DOUBLE

9 METALS SUBSTANCE HAVING 1-3 VALENCE ELECTRONS USUALLY LOSES ELECTRONS WHEN REACTING FOUND LEFT OF THE STAIR STEPS ON THE PERIODIC TABLE

10 PROPERTIES OF METALS MALLEABLE – CAN BE HAMMERED (FORMED) INTO SHEETS DUCTILE – CAN BE DRAWN INTO A WIRE CONDUCT ELECTRICITY AND HEAT LUSTER - SHINY

11 NONMETALS SUBSTANCE HAVING 5-7 VALENCE ELECTRONS USUALLY GAINS ELECTRONS WHEN REACTING FOUND RIGHT OF THE STAIR STEPS ON THE PERIODIC TABLE

12 PROPERTIES OF NONMETALS BRITTLE – CAN NOT BE FORMED INTO SHAPES DO NOT CONDUCT ELECTRICITY OR HEAT

13 METALLOIDS SUBSTANCES HAVING 3-5 VALENCE ELECTRONS CAN GAIN OR LOSE ELECTRONS WHEN REACTING ALONG THE STAIR STEPS ON THE PERIODIC TABLE Si, As, Ge, Sb

14 NOBLE GASES SUBSTANCE HAVING 8 (OR 2) VALENCE ELECTRONS DO NOT GAIN OR LOSE ELECTRONS – SO THEY DO NOT REACT (CALLED INERT) FOUND IN RIGHTMOST COLUMN OF PERIODIC TABLE

15 PERIODIC LAW ELEMENTS SHOW A REPEATING PATTERN WHEN ORGANIZED BY ATOMIC NUMBER

16 EXAMPLES ATOMIC SIZE, VALENCE ELECTRONS, AND CHEMICAL REACTIVITY EACH PERIOD GOES FROM 1 TO 8 VALENCE ELECTRONS (NOT INCLUDING THE “B” GROUPS

17 TRENDS ATOMS BECOME SMALLER ACROSS A PERIOD ATOMS BECOME LARGER DOWN A GROUP

18 NAMED FAMILIES IA – ALKALI METALS (EXCLUDING HYDROGEN) IIA – ALKALINE EARTH METALS VIIA – HALOGENS VIII – NOBLE GASES

19 FAMILY CHARACTERISTICS ALL HAVE THE SAME NUMBER OF VALENCE ELECTRONS SIMILAR CHEMICAL PROPERTIES

20 CHEMICAL STABILITY 8 ELECTRONS IN A VALENCE SHELL IS CALLED A STABLE OCTET 2 ELECTRONS IN A VALENCE SHELL IS A STABLE DUET

21 REACTIONS ELECTRONS MAY BE TRANSFERRED OR SHARED ATOMS REACT TO FORM STABLE VALENCE CONFIGURATIONS (8 OR 2 VALENCE ELECTRONS)

22 CHEMICAL BOND FORCE OF ATTRACTION (FOA) BETWEEN ATOMS DUE TO OPPOSITE CHARGES TYPES INCLUDE IONIC, COVALENT, AND METALLIC ALL INVOLVE MOVEMENT OF VALENCE ELECTRONS FORMATION IS EXOTHERMIC

23 ION ATOM WITH THE WRONG NUMBER OF ELECTRONS

24 CATION POSITIVELY CHARGED ATOM LOST 1 OR MORE ELECTRONS

25 ANION NEGATIVELY CHARGED GAINED 1 OR MORE ELECTRONS

26 IONIC BOND FOA DUE TO THE TRANSFER OF ONE OR MORE VALENCE ELECTRONS FROM ONE ATOM TO ANOTHER ATOMS ATTRACT DUE TO OPPOSITE CHARGES RESULTING COMPOUND IS IONIC COMPOUND

27 IONIC COMPOUNDS NEUTRAL REGULAR REPEATING PATTERNS CALLED CRYSTALS (NOT MOLECULE) HAVE STRONG BONDS CAUSING THEM TO BE BRITTLE SOLIDS AT ROOM TEMP, AND HAVE HIGH MP

28 IONIC CMPDS II SEPARATE INTO IONS (DISSOCIATE) WHEN DISSOLVED IN WATER AQUEOUS SOLUTIONS CONDUCT ELECTRICITY CALLED ELECTROLYTES

29 COVALENT BONDS FOA DUE TO SHARNG ONE OR MORE PAIRS OF VALENCE ELECTRONS, EACH ATOM CONTRIBUTING ONE ELECTRON IN A PAIR ELECTRON PAIR JUMPS BACK AND FORTH BETWEEN ATOMS

30 COVALENT BOND II TEMPORARY CHARGES THAT CAUSE ATTRACTION RESULTING COMPOUND IS CALLED COVALENT (OR MOLECULAR) CAN HAVE DOUBLE AND TRIPLE COVALENT BONDS

31 COVALENT COMPOUNDS NEUTRAL FORM MOLECULES (NOT CRYSTALS)

32 HAVE WEAK ATTRACTION FORCES BETWEEN MOLECULES CAUSING THEM TO BE GASES OR LIQUIDS AT ROOM TEMP AND TO HAVE LOW MELTING POINTS

33 COVALENT CMPDS II DO NOT DISSOCIATE IN WATER NOT USUALLY ELECTROLYTES

34 COVALENT CRYSTALS LARGE COVALENTLY BONDED STRUCTURES STRONG AND A VERY HIGH MP ONLY A FEW KINDS OF ATOMS CAN FORM THESE EXAMPLES: DIAMOND AND CARBORUNDUM

35 MOLECULE OR COMPOUND A MOLECULE IS TWO OR MORE ATOMS COVALENTLY BONDED A COMPOUND IS TWO OR MORE DIFFERENT ATOMS CHEMICALLY BONDED

36 DIATOMIC MOLECULE TWO ATOMS OF THE SAME ELEMENT COVALENTLY BONDED SEVEN DIATOMIC ELEMENTS: H, N, O, F, Cl, Br, and I HORSES NEED OATS FOR CLEAR BROWN EYES

37 METALLIC BONDS FOA CAUSED BY SHARING LOOSELY HELD VALENCE ELECTRONS AMONG MANY METAL IONS CAUSES PROPERTIES OF LUSTER, CONDUCTIVITY, MALLEABILITY, AND DUCTILITY

38 METALLIC BONDS II USUALLY BETWEEN LIKE ATOMS IN A PIECE OF THE ELEMENT TWO DIFFERENT METALS FORM MIXTURES CALLED ALLOYS, NOT COMPOUNDS MIXTURES STILL SHOW METALLIC PROPERTIES

39 PREDICTING BOND TYPES IONIC BOND FORMED BETWEEN A METAL AND A NONMETAL COVALENT BOND IS FORMED BETWEEN TWO NONMETALS METALLIC BOND IS FORMED BETWEEN TWO METALS

40 EXCEPTION HYDROGEN ALWAYS FORMS COVALENT BONDS EXCEPT WITH FLUORINE