What is an Atom? The smallest part of an element which retains the properties of that element.

Atom Nucleus Protons Neutrons Electrons http://mrdclassified.weebly.com/atoms.html

Proton Positively charged subatomic particle(s) that are found in the nucleus of an atom.

Neutron Neutral, subatomic particle(s) bearing no charge that are found in the nucleus of an atom.

Electron Negatively charged subatomic particle(s) that are found outside of the nucleus of an atom.

Subatomic Particles

Does an atom have a charge? NO, matter around us is neutral. So what can you tell me about the number of protons and electrons in an atom? Atoms are always neutral therefore protons always equal electrons.

The Periodic Table Elements are so periodic ! “Repeats at regular intervals”

Dimitri Mendeleev Russian chemist Published first version of periodic table in 1869 Put elements in order of increasing atomic mass All elements were not known at that time, but he was able to predict the elements that fit in the gaps.

Henry Moseley Early 20th century improved the table by arranging the elements , by atomic Number (#protons) This made it more clear Which elements were missing

the arrangement of electrons in the energy levels of a Bohr model How to read it Atomic Mass Symbol Represents the name of the chemical Represents the number of protons and neutrons in the nucleus 12 C Atomic Number Electron Configuration Represents the number of protons in the nucleus Represents the arrangement of electrons in the energy levels of a Bohr model 6 2 - 4

Do Now Atomic Mass = Atomic number = If an atom has a mass of 65 and an atomic number of 30 how many protons, neutrons, and electrons does it have?

Modern Periodic table arranged into periods 1-7 Horizontal rows of elements Side to side Increase in Atomic number from left to right Li Be B C N O F Ne

Families of Elements He Ne Vertical columns of elements Ar Up & Down Also referred to as Groups Share common characteristics or properties He Ne Ar Kr Xe Rn

Number of protons found in a nucleus, defines an atom Atomic Number Number of protons found in a nucleus, defines an atom

Total of protons and neutrons found in the nucleus of an atom Atomic Mass Total of protons and neutrons found in the nucleus of an atom

Metals Similar in many properties Luster/Shiny Malleable (can be pressed into sheets) Conduct heat and electricity Ductile (can be drawn out into wires)

Nonmetals Usually gases or brittle solids Most are poor conductors of heat and electricity Most are gases at room temperature

Metalloids Have some properties of both metals and nonmetals Along the stair step Ex: boron has luster but is a Poor conductor of electricity

Green – metals Yellow – nonmetals Blue - metalloids

PERIODIC PATTERNS Li Be B C N O F Ne Atoms increase in mass from the left side to the right side in each row.

More Patterns Atoms in the same family (group) increase in size from top to bottom. Ex: Na (sodium) is bigger than H (hydrogen) H Li Na K Rb Cs Fr

Chemical Activity Chemical activity decreases from left to right. Group 1 are very chemically active metals, Group 18 are chemically inactive gases. They are called Noble gases.