Claremont High School 2014 – 2015 Physical Science

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 “…part of the frustration you might remember about the periodic table could flow from the fact that, despite its being freely available to fall back on, a gigantic and fully sanctioned cheat sheet, it remained less than frickin’ helpful.”  - The Disappearing Spoon and Other True Tales of Madness

 The periodic table of elements organizes all of the different elements, or different types of atoms.  It is organized by increasing atomic number.

 Elements are divided into groups or families.  Each column of the periodic table contains one element family.

 Element families have similar traits because they have the same number of electrons in their outer energy levels.

 Some major element families include:  Noble gases ▪ Stable, do not combine easily with other elements  Halogens ▪ Highly reactive, toxic  Alkali metals ▪ Reactive, form similar compounds

 The element symbol is a one- or two-letter abbreviation derived from the element’s English or Latin name.  The atomic number is equal to the number of protons in the nucleus as well as the number of electrons in the electron cloud.

 The atomic mass is the average of the masses of all the element’s isotopes.  The atomic mass rounded to the nearest whole number represents that element’s most common isotope.

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 Mass number is the number of protons and neutrons in the nucleus.  Mass number is determined by rounding the atomic mass to the nearest whole number.  NOT on the periodic table

 Isotopes are atoms of the same element with different mass numbers.  Hyphen notation: Fluorine - 19

 Chlorine – 37  Atomic #: 17  Mass #:37  # of Protons:17  # of Electrons:17  # of Neutrons: 20

 Carbon – 12  Atomic #: 6  Mass #:12  # of Protons:6  # of Electrons:6  # of Neutrons: 6

 Sometimes an atom can lose or gain electrons. If this happens it becomes charged.  If it loses an electron, it becomes positive.  If it gains an electron, it becomes negative.

 If lithium loses one electron, its symbol is:  If oxygen gains two electrons, its symbol is: Li O

Na Atomic #: Mass #: # of Protons: # of Electrons: # of Neutrons:

Atomic #: 6 Mass #:12 # of Protons:6 # of Electrons:6 # of Neutrons:6 ?