Periodic Table and Properties of Elements

8/4/2019 Periodic Table and Properties of Elements

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Atoms and ions

Atoms

have no charge

Ions

Charged atoms

Cations ( + charged)

Anions ( - charged)


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Atomic number and atomic mass

Atomic number (Z) Number of protons = number of

electrons

Z = p+ = e-

Atomic mass (A)

Number of protons + number ofneutrons

A = p+ + no


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COMPLETE THE TABLE:SYMBOL Z A p+ e- no

Na 11 12

Fe 26 30

Rb+1

85 37

S-2 16 16


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Metalloids

Zigzag line dividing metals andnonmetals

Have properties of bothmetals and nonmetals

They are very goodsemiconductors (component

of microchips in electronics)


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Metalloids


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CHEMICAL FORMULAS Consists of the symbols of the elements

accompanied by subscripts to the right of the

symbols

Ex. H2C12H22O11


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CHEMICAL FORMULAS

Subscripts

tells the number ofatoms of the element on the left

C12H22O11

12 carbon; 22 hydrogen; 11oxygen atoms


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Rules for Writing Formulas

3. Write the symbol

for the MOREMETALLIC ELEMENT

first.


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Metallic propertyDECREASING METALLIC PROPERTY

INCREASING

METALLICPROP

ERTY


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EXAMPLE

SO2

Sulfur, the more

metallic element, iswritten first.

Oxygen is written last

since it is less metallic

There are 2 atoms for

oxygen, thus a subscript

of 2 is written after the

symbol


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Naming Binary Compounds

Binary compounds

Made up of two elements

Ionic compounds

Contains a metal + nonmetal

Covalent compounds

Contains two nonmetals


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Ionic compounds (metal + nonmetal)

Examples:

Na and Cl NaCl

Mg and S MgS

Rule:

Name the metal (Na is Sodium)

Name the nonmetal ending in

ide(Cl is

Chlorine + -ide= chloride)

NaCl is Sodium choride


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Ionic compounds (metal + nonmetal)

Examples:

Mg and O2 MgO2

Rule:

Name the metal (Mg is Magnesium)

Name the nonmetal ending in ide(O2

is

Oxygen + -ide= oxide)

MgS is Magnesium oxide


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Answer:

1.KI

2.CaBr2

3.Al2O3

4.Li3N5.Na2O

1.Potassium iodide

2.Calcium bromide

3.Aluminum oxide

4.Lithium nitride5.Sodium oxide


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Covalent Compounds

(nonmetal + nonmetal)

Examples:

C and O2 CO2

Si and C SiC Steps:

1. Name the elements in the order that

they appear in the formula

2. Drop the last syllables (or two/three) in

the final element and add ide.


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Covalent Compounds

(nonmetal + nonmetal)

Step 3.

Add prefixes to

the name ofeach element

to indicate the

number ofatoms.

PREFIX NUMBER

Mono- 1

Di- 2

Tri- 3

Tetra- 4

Penta- 5

Hexa- 6

Hepta- 7

Octa- 8


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CO2 is Carbon dioxide

carbon

CO2Oxygen + -ide isoxide Two indicates

the suffix Di-


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SiC is Silicon monocarbide

Silicon

SiCCarbon + -ide iscarbide No subscripts


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Exercise: Name the following

1.CSe2

2.SF6

3.CS2

4.CCl45.S4N2


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Answer:

1.CSe2

2.SF6

3.CS2

4.CCl45.S4N2

1. Carbon diselenide

2. Sulfur hexafluoride

3. Carbon disulfide

4. Carbon tetrachloride

5. Tetrasulfur dinitride

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Periodic Table and Properties of Elements