Non‐metal with a non‐metal


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EIT Chemistry Review F2009
Dr. J.A. Mack
Download available at:
www.csus.edu/indiv/m/mackj/
Or look for Jeffrey Mack under CSUS faculty web pages Part 1
2
Where do we begin… The Periodic Table
Dmitri Mendeleev (1834 ‐ 1907)
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Chemistry is really…
Chem is try
To do chemistry, you must:
Practice
Practice
Practice
4
The modern periodic table is defined by:
Groups (families) (columns down)
Periods (rows across)
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1

Ch. 2

Tin is in group 4A (14) in the 5th period.
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Periodic Table: Metallic arrangement

1

IA

2

1

IIA

18 VIIIA
13 14 15 16 17 IIIA IVA VA VIA VIIA

2

3

4

5

6

7

8

9 10 11 12

3

IIIB IVB VB VIB VIIB

VIIIB

IB IIB

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Metalloids

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somewhere in

6

between

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metals and

non‐metals 9

Periodic Table: Metallic arrangement

1

IA

2

1

IIA

18 VIIIA
13 14 15 16 17 IIIA IVA VA VIA VIIA

2

3

4

5

6

7

8

9 10 11 12

3

IIIB IVB VB VIB VIIB

VIIIB

IB IIB

4

5

Metals

6

Nonmetals

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Ch. 2 8

Chemical Symbols and Formula:

Elements: Molecules:

H = hydrogen

O = oxygen

C = carbon
H2 = hydrogen O2 = oxygen H2O = water

Uh‐Oh! this is confusing…
Yes it is… Get over it and get used to it!

CO2 = carbon dioxide

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2

Which elements do we need to know? Start here as a minimum…
As many as possible!
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Atom: The smallest divisible unit of an element Compound: A substance made of two or more atoms Ion: A charged atom or molecule Cation: Positive ion Anion: Negative ion
NOMENCLATURE Format for naming chemical compounds using prefixes, suffixes, and other modifications of the names of elements which constitute compounds.
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Al

Aluminum

B

Boron

Cr

Chromium

Co

Cobalt

Cu

Copper

F

Fluorine

Fe

Iron

Au

Gold

Pb

Lead

Ag

Silver

Hg

Mercury

P

Phosphorus

K

Potassium

Na

Sodium

S

Sulfur

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inert or “noble” gasses:

Metals form Cations non‐metals form anions Metalloids can do both
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3

Ion Charges:
+1 +2
Variable

+3 ‐3 ‐2 ‐1

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Chemical Nomenclature:

Go to the lab page on my website and download the worksheet!

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Compounds fall into one of two classes:

Inorganic Salts
metal cation +
non‐metal or polyatomic anion

Molecules
non‐metal +
non‐metal (no cations or anions)

The two use different formalisms for naming…
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Binary Compounds: Metal & non‐Metal

Metal of fixed oxidation (charge) state combined with a non‐metal.

Examples:

non‐metal takes on “ide” suffix

Cation Anion Formula

Name

K+

Cl−

Ca2+

O2‐

Na+

S2‐

Al3+

S2‐

KCl CaO Na2S Al2S3

Potassium chloride Calcium Oxide Sodium sulfide Aluminum sulfide

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4

Metals of variable charge (transition) with a non‐metal

Examples:

modify transition metal name with roman numeral

Cation Anion Formula

Name

Pb2+

Cl−

PbCl2

lead (II) chloride

pronounced: lead ‐ two ‐ chloride

Pb4+

Cl−

PbCl4

lead (IV) chloride

Fe3+

O2−

Fe2O3

Iron (III) oxide

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Ternary Compounds: Those with three different elements metal of fixed charge with a complex ion

Cation Anion Formula

Name

K+

OH−

KOH

Potassium hydroxide

Ca2+

OH− Ca(OH)2 Calcium hydroxide

Na+

SO24−

Na2SO4

Sodium sulfate

Al3+

SO24− Al2(SO4)2 Aluminum sulfate

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Some common polyatomic ions:

NH4+ H3O+ CO32– HCO32–
NO2– NO3– SO42– SO32– PO43– C2H3O2–

ammonium hydronium carbonate hydrogen carbonate
or bicarbonate nitrite nitrate sulfate sulfite phosphate acetate

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Metal of variable charge transition with a complex ion

Cation Anion Formula

Name

Fe3+

NO3− Fe(NO3)3 Iron (III) nitrate

Fe2+

NO2− Fe(NO2)2 Iron (II) nitrite

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5

Non‐metal with a non‐metal

When non‐metals combine, they form molecules. They may do so in multiple forms:

CO

CO2

Because of this we need to specify the number of each atom by way of a prefix.

1 = mono

2 = di

3 = tri

4 = tetra

5 = penta

6 = hexa

7 = hepta
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Writing formulas for acids and Bases
•An acid is a substance that produces H+ when dissolved in water. •Certain gaseous molecules become acids when dissolved in water. •A base produces OH− when dissolved in water. •Bases often are Group I and Group II hydroxide salts.
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Examples: Formula BCl3 SO3 NO

Name: boron trichloride sulfur trioxide nitrogen monoxide

we don’t write:

nitrogen monooxide or mononitrogen monoxide

N2O4

dinitrogen tetraoxide

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Type I Acids: Acids derived from –ide anions. The names for these acids follows the formula:

“hydro” + the root of the ide anion + ic “acid”

Anion: chloride

Acid: HCl

Name: hydrochloric acid

fluoride

HF

hydrofluoric acid
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H+ and S2‐
it takes 2 H+ to cancel one S2‐
H2S
hydro sulfuric acid
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CO2 carbon monoxide P2O5 nitrogen trihydride

carbon dioxide CO diphosphorous pentaoxide NH3
(ammonia)

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Examples:
Anion:
(nitrate) NO3−

Acid: HNO3

Name: nitric acid

(sulfate) SO24−

H2SO4

sulfuric acid

(acetate) C2H3O2−

HC2H3O2

acetic acid vinegar

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Common Names:
H2O ammonia CH4 NO N2O

water NH3 methane nitric oxide nitrous oxide

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7

It’s time to play…

sodium chloride sodium nitrate Ca3N2 Fe(NO3)3 PbS

NaCl
NaNO3 calcium nitride
iron (III) nitrate or ferric nitrate*
lecahda(nIIn) seullf6ide
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Modern Atomic Theory:
•Atoms are made of protons, neutrons and electrons. •The nucleus of the atom carries most of the mass. • It consists of the protons and neutrons surrounded by a cloud of electrons.
The charge on the electron is –1 The charge on the proton is +1 There is no charge on the neutron
The Atomic Number or number of protons in the nucleus defines an element.
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Practice: N2SO4 barium carbonate FeO

sodium sulfate BaCO3 Iron (II) oxide

zinc phosphide NiBr2

Zn3P2 nickel (II) bromide

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The Composition of an Atom:
The atom is mostly empty space
•protons and neutrons in the nucleus. •the number of electrons is equal to the number of protons. •electrons in space around the nucleus.
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8

Atomic Number, Z
An element’s identity is defined by the number of protons in the
nucleus: Z

13 Al 26.981

Atomic number Atom symbol
Atomic weight

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Example: Selenium‐75

75 protons + neutrons
34 protons

3745Se

protons = 34

electrons = 34

neutrons = 75‐34 = 41
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Ch. 2
Isotopes, Atomic Numbers, and Mass Numbers

Elemental Isotopic Symbols: For a given element “X”, an
isotope is written by:
Atomic number (Z) = number of protons in the nucleus.

Mass number (A) = total number of nucleons in the nucleus (i.e., protons and neutrons).

One nucleon has a mass of 1 amu (Atomic Mass Unit) a.k.a “Dalton” or u

XA
Z

Isotopes have the same Z but different total number of nucleons (A).

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Ch. 2
The average weighted atomic mass is determined by the
following mathematical expression:

Average mass of a Cl atom
m Cl (u) =

mass of a Cl‐35 atom
m Cl‐35 ×

fraction that are
Cl‐35
abundance
of Cl‐35

mass of a Cl‐37 atom
+ m Cl‐37 ×

fraction that are
Cl‐37
abundance
of Cl‐37

35.45 u = 34.96885u × 0.7553 + 36.96590 × 0.2447
(4 sig. fig)
This is the value that is reported on the periodic table.
Note that: 0.7553 + 0.2447 = 1.0000 (100%)
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9

Ch. 2
Avogadro’s Number and the Mole
The concept of a mole is defined so that we may equate the amount of matter (mass) to the number of particles (mole). The Standard is based upon the C‐12 isotope. The mass of one 12C‐atom is 1.99265 × 10‐23 g.
The atomic mass of 12C is defined as exactly 12 u.
Therefore: 1u = (the mass of one 12C atom ÷12) = 1.66054 × 10‐24g = 1.66054 × 10‐27 kg
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Molar Masses

Ch. 2

Since we can equate mass (how much matter) with moles
(how many particles) we now have a conversion factor
that relates the two.

mols × molar mass (g/mol) = grams

The Molar Mass of a substance is the amount of matter that contains one‐mole or 6.022 × 1023 particles.
aka: Avogadro's number (NA)
The atomic masses on the Periodic Table also represent the molar masses of each element in grams per mole (g/mol)
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Avagagro’s Number

Ch. 2

Since one mole of 12C has a mass of 12g (exactly), 12g of 12C contains 6.022142 × 1023 C‐12 atoms.

But carbon exists as 3 isotopes: C‐12, C‐13 &C‐14 The average atomic mass of carbon is 12.011 u.

From this we conclude that 12.011g of carbon contains

6.022142 × 1023 C‐atoms

Is this a valid assumption?

Yes, since NA is so large, the statistics hold.
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Ch. 2
So if you have 12.011g of carbon… you have 6.022×1023 carbon atoms!
So if you have 39.95g of argon… you have 6.022×1023 argon atoms!

if you have a mole of dollar bills… you are Bill Gates… you have 6.022×1023 bucks!

and if you have 6.022×1023 avocados…

you have…

a “guacamole”

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Non‐metal with a non‐metal