Basic chem mine

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Basic Chemistry

Things you need to know

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Matter

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MatterEverything in

the universe is composed of matter.

Matter is anything that occupies space or has mass

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Measuring MatterMass –

quantity of matter an object has

Weight – pull of gravity on an object

Space Moon Earth

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Elements

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ElementsPure

substances that cannot be broken down chemically into simpler kinds of matter

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ElementsIn total,

117 elements have been observed as of 2008

Of which 94 occur naturally on Earth.

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Principle Elements in Organisms

90% of the mass of an organism is composed of 4 elements OxygenCarbonHydrogen Nitrogen Carbon Ring

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ElementsEach element unique chemical symbol

Consists of 1-2 letters

First letter is always capitalized

Use Latin/Greek names or neo-Latin names

PotassiumLatin: kalium

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KPotassium39.0983

2881

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ElementsEach element unique chemical symbol

Consists of 1-2 letters

First letter is always capitalized

Use Latin/Greek names or neo-Latin names

IronLatin: ferrum

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FeIron

55.845

28142

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Elements

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CCarbon12.0107

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Common parts of information found in an element’s box.

Atomic Number

Atomic Mass

Shells

Element Symbol

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AtomsThree Parts

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AtomsThe simplest particle

of an element that retains all the properties of that element

Properties of atoms determine the structure and properties of the matter they compose

Our understanding of the structure of atoms based on scientific models, not observation

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Basic Atom PartsThe Nucleus Central Core Made of

a) Protons (P+)b) Neutrons (N)

It is surrounded by an Cloud of particles

c) Electrons (e—)

Nucleus

Cloud

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The NucleusCorePositively

chargedContains most

of the mass of the atom

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The Protons (P+)All atoms of a given

element have the same number of protons

Number of protons called the atomic number

Number of positive protons are balanced by an equal number of negative electrons

Protons are attracted to the electrons in orbit around the atom

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CCarbon12.0107

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P

P

P

PN

N

N

N

NN

PP

P

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The Neutrons (N)The neutron

number varies slightly among atoms of the same element

Different number of neutrons produces isotopes of the same element

Hydrogen 11P, 0NMass # = 1



Isotopes of Hydrogen

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Atomic MassProtons & neutrons

are found in the nucleus of an atom

Protons and neutrons each have a mass of 1 amu (atomic mass unit)

The atomic mass of an atom is found by adding the number of protons & neutrons in an atom

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Electrons (e—)Negatively charged

high energy particles with little or no mass

Travel at very high speeds at various distances (energy levels) from the nucleus

The areas where electrons travel are called electron clouds

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Electrons (e—)Electrons

travel in regular patterns within the cloud called orbitals.

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Electrons (e—)In the clouds they

are arranged in to layers called shells

Electrons in the same energy level are approximately the same distance from the nucleus

Outer energy levels have more energy than inner levels

Each level holds only a certain number of electrons

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Electrons (e—)The Octet Rule:

Atoms are most stable when they have 8 electrons in their outer-most shell.

The exception is the first shell which is most stable with TWO electrons.

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Electrons (e—)If you know the

Atomic Number and Mass Number of an element and the maximum number of electrons in each electron shell you can draw a diagram of the element.

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CCarbon12.0107

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Energy LevelsAtoms have 7 energy levelsThe levels are

K (closest to the nucleus)LMNOPQ (furthest from the nucleus)

The K level can only hold 2 electrons

Levels L – Q can hold 8 electrons (octet rule)

1. 22. 83. 84. 85. 86. 87. 8

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4e—

Energy Levels

6 N6P+

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CCarbon12.0107

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2e—

Shell K Shell L

Nucleus

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8e—

Energy Levels

19 N19 P+

2e—

Shell K Shell L

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KPotassium39.0983

2881

8e—

Shell M

1e—

Shell N

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? e—

Energy Levels

? N? P+

? e—

Shell K Shell L

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NaSodium

22.98976

? e—

Shell M

? e—

Shell N

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8e—

Energy Levels

11 N11 P+

2e—

Shell K Shell L

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NaSodium

22.98976

1e—

Shell M

0e—

Shell N

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? e—

Energy Levels

? N? P+

? e—

Shell K Shell L

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ClChlorine35.453

? e—

Shell M

? e—

Shell N

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8e—

Energy Levels

17 N17 P+

2e—

Shell K Shell L

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ClChlorine35.453

1e—

Shell M

0e—

Shell N

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? e—

Energy Levels

? N? P+

? e—

Shell K Shell L

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OOxygen15.9994

? e—

Shell M

? e—

Shell N

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6e—

Energy Levels

8 N8 P+

2e—

Shell K Shell L

8

OOxygen15.9994

0e—

Shell M

0e—

Shell N

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Valence ElectronsValence

electrons are the outermost electrons of an atom

They determine the number of chemical bonds formed by the atoms of a given element.

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Valence ElectronsHow many

electrons are needed in the outer shell for the atom to be stable?

4e—6 N

6P+

2e—

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CCarbon12.0107

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electrons are needed in the outer shell for the atom to be stable?

Apply the octet rule

Wants 8 to be stable

Needs 4

4e—6 N

6P+

2e—

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CCarbon12.0107

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more electrons are needed in the outer shell to make a stable atom?

? e—

? N? P+

? e—

? e—

8

OOxygen15.9994


more electrons are needed in the outer shell to make a stable atom? 8 N

8 P+6 e

—2 e

—8

OOxygen15.9994

Needs 2 electrons

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BondingWhy atoms join forces

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Covalent BondAtomic bond

where electrons are shared evenly.

ExamplesH2 or H:HCH4

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Polar-Covalent BondAtomic bond

where electrons are shared unevenly giving a slight charge to the molecule.

Ex: H2O (hydrogen bonding)

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Ionic BondAtomic bond

where electrons are not shared evenly

Results in a charged molecule.

Charged atoms are called ions.

Ex: NaCl (Sodium Chloride)

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Ionic BondAtomic bond where

electrons are not shared evenly

Results in a charged molecule.

Ex: NaCl (Sodium Chloride)

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Writing Chemical Formulas

Determine the different kinds of atoms.HydrogenCarbonOxygen

Count the number of atoms of each type.Hydrogen — 12Carbon — 6Oxygen — 6

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Writing Chemical Formulas

Count the number of atoms of each type.Hydrogen — 12Carbon — 6Oxygen — 6

Write the chemical symbol followed by the number in subscript

C2H12O6

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