The Periodic Table

Claremont High School 2014 – 2015Physical Science

Meet the elements

http://www.youtube.com/watch?v=d0zION8xjbM

The Disappearing Spoon Excerpt

“…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

What is the Periodic Table?

The periodic table of elements organizes all of the different elements, or different types of atoms.

It is organized by increasing atomic number.

How are elements organized?

Elements are divided into groups or families.

Each column of the periodic table contains one element family.

How are elements organized?

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

How are elements organized?

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

How do we interpret the cells in the periodic table?

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.

How do we interpret the cells in the periodic table?

The atomic mass is the average of the masses of all the element’s isotopes.

The atomic massrounded to the nearestwhole number representsthat element’s most common isotope.

Isotopes and Atomic Mass

http://phet.colorado.edu/en/simulation/isotopes-and-atomic-mass

What is the mass number?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

What does mass number tell us about isotopes?

Isotopes are atoms of the same element with different mass numbers.

Hyphen notation: Fluorine - 19

What does mass number tell us about isotopes?

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

Check for understanding

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

What are ions?

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.

What are ions?

If lithium loses one electron, its symbol is:

If oxygen gains two electrons, its symbol is:

Li

O

73

168

+

2-

Check for understanding

Na2311

+Atomic #:

Mass #:# of Protons:

# of Electrons:# of Neutrons:

Check for understanding

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

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