# Building Blocks of Matter

## Presentation on theme: "Building Blocks of Matter"— Presentation transcript:

Building Blocks of Matter
Atoms Building Blocks of Matter

Atoms Smallest particle of matter to have similar properties
Atoms are particles of an element

Subatomic Particles All atoms are made up of three primary subatomic particles: Protons Positively-charged particle in the nucleus Has a relative mass of 1 Atomic Mass Unit (amu) Neutrons Neutrally-charged particle in the nucleus New theories suggest that Neutrons are slightly larger than Protons, and may be made from a Proton and an Electron that have combined

Subatomic Particles Electrons Quarks
Negatively-charged particle outside the nucleus Has NO relative mass Actual mass is 1/1936th of 1 amu Quarks Smaller particles that make up Protons, Neutrons, and Electrons Have their own branch of Theoretical Physics

Properties of Atoms Atomic Number Atomic Mass
Differentiates between elements Equal to the number of protons Atomic Mass Equal to the number of Nucleons (particles in the nucleus, Protons and Neutrons)

Properties of Atoms Normal atoms are neutral, having the same number of protons and electrons If an atom gains electrons the atom becomes negatively charged If an atom loses electrons the atom becomes positively charged

NOT ALL OF THESE ARE NECESSARY
Writing Elements Write the Symbol Write the Mass Number at the upper-left of the symbol Write the Atomic Number at the lower-left of the symbol Any charge goes at the upper-right hand corner NOT ALL OF THESE ARE NECESSARY +4 Ag 108 47

Cl Counting Particles 35 17 Protons = Atomic Number Neutrons =
Atomic Mass – Atomic Number Electrons = Protons ADJUST FOR CHARGE Negative charge means MORE electrons Positive Charge means LESS electrons Cl 35 17

Charge Atoms will gain, lose, or share electrons to become chemically stable “Rule of Octet” Atoms in Groups 1 – 14 will lose electrons down to zero become positive ions Atoms in Groups 15, 16, 17, will gain electrons up to eight become negative ions Group 18 will not gain, lose, or share electrons Have 8 electrons anyway

Oxidation Number The number of electrons an atom will gain, lose, or share in order to become stable The GROUP number indicates the number of outer-shell electrons Groups 1, 2 Groups (except He) Always 4 or less Go with the LOWER number of the two possibilities

The Periodic Table Periodic means in a regular, repeating fashion
Many early designs were based on use, physical properties, and even spelling

Mendeleev’s Contributions
Organized first working Periodic Table according to chemical properties and atomic mass Left gaps for undiscovered elements He was able to predict many properties of these undiscovered elements based on their location “Ekasilicon”

Periodic Table Rows are called PERIODS
Properties of elements repeat across a Period Columns are called GROUPS or FAMILIES Elements in a family have the same Chemical Properties

Group 1 Alkali Metals Highly reactive metals
Have one outer shell electron

Group 2 Alkaline Earth Metals Reactive metals
Have two outer shell electrons

Groups 3 – 12 Transition Metals “normal” metals
Have one to ten outer shell electrons

Metals v. Nonmetals METALS Located to the left of the Stair-Step
Lustrous Malleable & Ductile Good conductors of heat and electricity Solid at room temperature (except Hg) NONMETALS Located to the right of the Stair-Step Waxy or dull Brittle Poor conductors of heat and electricity (good insulators) Gas at room temperature (some exceptions)

Metalloids May have properties of metals and nonmetals
Located on the stair-step Some are semiconductors: they only conduct electricity under certain conditions This makes metalloids excellent switches for computers

Group 17 Halogens Highly reactive nonmetals
Means “Salt Former” Highly reactive nonmetals Have seven outer shell electrons

Group 18 Noble Gases Completely unreactive nonmetals
Will not bond with any atom Have a full outer shell of electrons Eight for all but Helium He has two outer shell electrons

Chemical Properties Based on the number of Valence electrons
Electrons on the outside of the atom Called valence shell electrons, outer shell electrons Each element in a group has the same number of valence shell electrons Groups 1, 2 is the group number Groups 13-18, drop the “1” Helium has 2 Groups 3-12 use a different set of electrons

Drawing a model of an atom
Draw a nucleus List the number of protons and neutrons in the nucleus Add energy levels for the number of electrons An energy level can hold electrons equal to the number of elements in that Period 2, 8, 8, 18, 18, 32, 32

Differing Atoms of the Same Element
Isotopes Atoms of an element with a different number of neutrons Has the same chemical and physical properties as any other isotope of that element

Various Isotopes

Differing Atoms of the Same Element
Allotropes Named when two or more natural or physical forms of an element exists Ex. for Carbon: Graphite, Diamond, Buckminsterfullerenes Ex. for Oxygen: O2, O3 - Ozone

Allotropes of Carbon

Allotropes of Oxygen

REVIEW Atoms Elements Subatomic Particles Atomic Number Atomic Mass
Charge Periodic Table Mendeleev Periods Groups Families Metals Nonmetals Drawing Atoms Isotopes Allotropes