Earth Chemistry Chapter 8

Matter 8.1 What is Matter?

What is Matter? Matter takes up space and has mass. Mass is the amount of matter in an object Different types of matter have different Physical and Chemical Properties.

Physical and Chemical Properties Physical Properties Characteristics that cam be observed without changing composition Examples Density Color Boiling Point Conductivity Chemical Properties Substances interact to form different types of matter Examples Corrosive Acid/Base Combustible Oxidizer

Atoms and Elements Matter is made of elements. Substances that have chemical and physical properties >90 natural elements Only 8 elements make up 98% of Earth’s crust O, Si, Al, Fe, Ca, Na, K, Mg. Atoms are the smallest unit of an element that still retain properties. Cannot be broken down smaller 1 million atoms side by side make the thickness of a piece of paper

Subatomic Particles Protons and Neutrons are found in the nucleus Proton (+), Neutron (neutral) Electrons surround the nucleus in the electron cloud. Electron (-)

Elements are arranged according to properties (NOVA Elements – Periodic Table)

Periodic Table Arranged by Properties of metals Atomic number Properties of the elements Properties of metals Malleable, good conductors, high MP, luster, ductile, give up electrons easily. Properties of non metals Not good conductors, brittle, low MP. Do not give up electrons easily

Metaloids Have properties of both metals and non metals. Found along the stair step line on the periodic table.

Periodic Table Atomic Number Mass number Number of Protons Number of Electrons Mass number Protons + Neutrons Amu - atomic mass unit.

Quiz Which letter is the atomic mass? B Which letter is the element’s atomic number? A

Quiz Carbon has how many protons? 14 is Silicon’s _____. 6 14 is Silicon’s _____. Atomic Number How much mass does one oxygen atom have? 15.999 amu

Quiz How many electrons does potassium have? 19 = atomic number How many neutrons does potassium have? 39-19=20

NOVA Elements Elemental Earth

Isotopes Atoms of the same element that differ from each other their mass number. Same number of protons, different number of neutrons. Hydrogen, Deuterium, Tritium.

Isotopes Movie

Combinations of Atoms 8.2

Compounds 2 or more elements chemically combined Creates a new substance with properties that differ from the original elements. NaCl, H2O, CaCO3 Combining Elements

Energy Levels An electron can only occupy 1 energy level at a time. An atom can contain many energy levels. Energy levels can only hold a max number of electrons. 2n2 ; n=energy level

How many electrons can the 1st energy level hold? 2(1)2 = 2

How many electrons can energy level 2 hold? 2(2)2 = 8

How many electrons can energy level number 3 hold? 2(3)2 = 18

Bohr Model Shows protons and neutrons in the nucleus. Electrons in energy levels around nucleus. How they form compounds is based on their electron arrangement.

Bohr Model Different elements have different # of energy levels Period Valence electrons are the electrons in the outer most energy level Happy with eight

Period = # of energy levels Group = Valence electrons

Electron Dot Diagram A shorthand notation to show the number of valence electrons in an atom. Easier then Bhor diagrams Also called Lewis Symbols

Which is the correct dot diagram for Neon?

Which is the correct dot diagram for chlorine?

Chemical Bonds Produced by the interactions of electrons Interactions based on outer shell electrons Form bonds by sharing or transferring electrons.

Ionic Bonds Transfer of electrons Bond between a metal and non metal element Ions combine to form ionic bond Forms a strong bond

Ionic Bond Movie

Covalent Bonds Atoms share electrons to form chemical bonds. Forms a weaker bond.

Covalent Bond Movie

Chemical Formulas Represents the elements a compound contains Indicates the relative number of atoms in each element Numbers are represented by subscript.

What elements are present in this compound? H= Hydrogen O = Oxygen

How many atoms of each element are there in water? Hydrogen = 2 Oxygen = 1

What elements are present in this compound? Na = Sodium O=Oxygen H=Hydrogen

How many atoms of each element are there in Sodium Hydroxide? Sodium = 1 Oxygen = 1 Hydrogen = 1

What elements are present in this compound? Ca=Calcium P=Phosphorus O=Oxygen

How many atoms of each element are there in Calcium Phosphate? This one is tricky! Calcium=3 Phosphorus=2 Oxygen=8

Mixtures Material that contains two or move substances that are not chemically combined. Substances keep their individual properties. Can be separated by physical means Rocks, soil, air, smog

Solution Mixture in which one substance is uniformly dispersed in another. Salt water Alloy A solution of two or more metals. Structure of an Alloy