Atomic Structure

Subatomic Particles Proton Positive charge + Mass of 1 amu Found in the nucleus # of protons = atomic number 11 Na Sodium

Subatomic Particle Neutrons Neutral charge Mass of 1 amu Found in the nucleus Mass number – Protons = Neutrons

Subatomic Particles Electrons Negative charge - 1/2000 th amu Found outside of the nucleus in the electron clouds # of electrons = # of protons

Particles of Atoms Atoms are neutral because there is an even number of protons (+) and electrons (-) Carbon has 6 + protons 6 – electrons 0 Neutral charge

Subatomic Particle LocationChargeAtomic Mass Unit ProtonNucleus+ Positive 1 amu NeutronNucleus= Neutral 1 amu ElectronElectron cloud - Negative 1/2000 th

Atomic Number The number of protons in the nucleus This number NEVER changes!!! 11 Na Sodium

Mass Number vs. Atomic Mass Mass number is the sum of the protons and the neutrons Protons + Neutrons = Mass Number Atomic Mass is the average mass of the isotopes of that element 11 Na Sodium

Electron Placement Location depends on how much energy the electron has Each energy level can only hold so many electrons Level 1: 2 electrons Level 2: 8 electrons Level 3: 18 electrons

Organizing the Elements Dmitri Mendeleev discovered the pattern among the elements arranging them in order of atomic mass Henry Moseley arranged them in order of their atomic number Periodic means “ a regular repeating pattern”

Data on Elements One square for each element that includes the: Atomic number Chemical Symbol and Name Average Atomic Mass 11 Na Sodium

The Periodic Table Properties of elements can be predicted by their location PERIODS Horizontal rows – 7 periods

Hint: a sentence usually ends in a period Goes from highly reactive metals to very unreactive gases Tells you how many energy levels the atom has Periods or Rows

How many energy Levels? Lithium (Li) Beryllium (Be) Calcium (Ca) Oxygen (O) Mercury (Hg)

The Periodic Table GROUPS or FAMILIES 18 Vertically aligned columns Hint: Family trees grow up and down

Groups or Families Elements in a group have similar characteristics – both physical and chemical properties Clue to how many valence electrons there are in the outer shell (for families 1,2, 13-18)

Valence Electrons Lithium (Li) Magnesium (Mg) Sodium (Na) Nitrogen (N) Krypton (Kr) (happy 8)

Review How are Families aligned? How are Periods aligned? Which one tells you the valence electrons? Which one tells you the number of energy levels?

Review some more Which is more similar to Carbon (C)? Nitrogen (N) or Tin (Sn) Boron (B) or Silicon (Si)

Metals Location Left of the zig-zag line

Metals Physical properties Shiny Ductile Can be drawn into long, thin wire Malleable Can be hammered/rolled into flat sheets Conductivity Some are magnetic

Metals Chemical Properties Reactivity – usually lose electrons Corrosion is an example of reactivity Pattern from left to right Lithium (Li)Neon (Ne) Highly reactive Non reactive

Alkali Metals Group or Family 1 Lose 1 electron Never found uncombined in nature Some are soft and can be cut with a knife

Examples of Alkali Metals Potassium Lithium Sodium

Alkaline Earth Metals Group or Family 2 Tend to lose 2 electrons Less reactive than Group 1 Fairly hard, gray- white

Alkaline earth metals

Transition Metals Groups 3-12 Most are hard and shiny Gold, tin, copper Good conductors Colorful

Metals in Mixed Groups Parts of Groups Not as reactive Most common: aluminum, tin, lead

Two rows at the bottom Part of Period 6 and 7 Lanthanides usually used to make alloys (metal solution) Only 2 actinides occur naturally- the rest are created artificially LANTHANIDE ACTINIDES

Trends: Atoms get smaller as you go left to right. They get bigger as you go top to bottom

Synthetic Elements All elements following Uranium are made with particle accelerators Element 93 and above Particle accelerators crash nuclei into each other

Non-Metals and Metalloids Vital for life on Earth Oxygen Carbon Wide variety of properties among these elements

Properties of Non-Metals Opposite of metals Poor conductors Solid nonmetals are dull and brittle Not malleable Physical properties 10 of 16 are gases at room temp Bromine is liquid at room temp usually have a lower density

Properties of Non-Metals Chemical Properties Reactive with other elements (flourine is the most reactive Family 18 is non reactive Usually receive electrons from metals when combining or they share electrons with other non metals

Non Metals Carbon Family 14 Found in all living things Many fuels are carbon based

Non-Metals Nitrogen Family 15 Contains 2 non-metals N is 80 % of atmosphere Occurs as a diatomic molecule (N 2 ) N gas is hard to use so it is changed to a usable form by some bacteria (Nitrogen fixation) Also found in fertilizers

Non-Metals The Oxygen family 16 3 non metals O, S, and Se Oxygen is a Diatomic molecule (O 2 ) and as O 3 which is OZONE Sulfur is also common

Non-Metals The Halogen family 17 “salt forming” Very reactive! Tends to gain or share an electron Flourine is extremely reactive!

Non Metals The Noble gases family 18 Very stable and non reactive Commonly used in neon lights All exist in the atmosphere

Hydrogen “all by myself” Makes up more than 90% of atoms in the universe Rarely found on earth Most is combined with O to form water

Metalloids On the zig zag border NOT aluminum Characteristics of both metals and non metals Silicon is most common Used to make semiconductors because of varying conductivity

Metalloids

We are done!! Stand up, stretch and take a bow!!!