Positive Charge

​

Found in the Nucleus

​

Has mass! (1 AMU)

​Proton

Neutral/No Charge

​

Found in the Nucleus

​

Has mass! (1 AMU) ​

​Neutron

​Negative Charge

​

Found outside the Nucleus

​

Has very very little mass​

​Electron

​How to find Protons, Neutrons, & Electrons

​# of  protons = atomic #

because # of protons determines an element's atomic identity

​

# of neutrons = mass #  - atomic #

because protons and neutrons together make the atomic mass

(round to the nearest whole number!!!)

​

# of electrons = # of protons, if charge = 0

because protons and electrons must cancel each other out

​Periodic Table of Elements

• ​Created by Dimitri Mendeleev

• ​Organized by ATOMIC NUMBER

  ​

  • ​Why? - Atomic number is the number of protons.

  • This is the only subatomic particle unique to every element!

​GROUPS

​18 Vertical columns of the periodic table.

​

Most tell us the number of valence electrons!

​PERIODS

​7 horizontal rows of the periodic table.

​

Tell us the number of electron shells!

​Families/Groups

Each family has a specific name .

• ​Families share similar chemical AND physical properties

• ​

• ​Families share the same number of valence electrons (same reactivity)

​​Elements on the periodic table can be grouped into families based on their chemical properties.

​Main Families

• ​Alkali Metals: 1 valence electron, metals, extremely reactive

• ​Alkaline Earth Metals: 2 valence electrons, metals, malleable

• ​Transition Metals: Good conductors of heat and electricity, found freely or in compounds

• ​Halogens: 7 valence electrons, nonmetals, extremely reactive

• ​Noble Gases: 8 valence electrons, nonmetals (gas), NON REACTIVE

  • (Full shell of electrons = happy)