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Transcript of Chapter 4, Section 4.2: Organizing the El Chapter 4, Section 4.2: Organizing the Elements How did...

• Chapter 4, Section 4.2: Organizing the Elements

How did Mendeleev discover the pattern that led to the periodic table?

How are the elements organized in the modern periodic table?

• Section 4.2: Learning Objectives

Describe how the elements are organized in the modern periodic table: including the order, the regions, family/groups, and periods.

7a. Students know how to identify regions corresponding to metals, nonmetals, and inert gases

• • apk

• Periodic Table of Elements Is organized like a calendar by • Columns and rows

• • columns (family groups) • rows (periods) • location, location, location, predicts the element’s properties

• Eight Basic Family Groups

• Seven Periods

• • Russian scientist in the 19th century.

• In 1836, developed the first P.T. of Elements with just 63 elements.

• Noticed a repeating pattern of properties in the elements and grouped them by similarities.

Dmitri Mendeleev

• • Recorded the properties (both physical and chemical) of the elements on cards. • Arranged the elements by repeating properties and by increasing mass (from lightest to heaviest), a mistake he did not know yet. • “periodic” means a repeating pattern.

Dmitri Mendeleev

• • He was able to use his P.T. to predict correctly the properties and mass of the missing elements yet to be discovered.

• The Modern Periodic Table or Elements • The Table is divided into two main parts by the zig-zag

line, and sub-divided in to three classes. 1. Metals on the left, 2. Nonmetals on the right, 3. Rare

Earth Metals on the bottom of the chart. • One special group along the zig-zag line: Metalloids

(Semimetals)

• Follow the Protons, They’re the Pros • The PT is arranged by the number of PROTONS. • The protons are the “Pro’s”, they’re the boss. • Starting with the atom that has only one proton,

HYDROGEN • Hydrogen has one proton, one electron, and NO

neutrons. • the PT contains more than 100 elements. • Arranged in order of increasing Atomic Number, starting with #1, Hydrogen.

• • Hydrogen, #1, the lightest, with one proton, (and 1 electron) and atomic mass of 1. (no neutrons)

• Helium, #2, with two protons, (and 2 electrons) and atomic mass of 4. (with 2 neutrons)

• Finding Data on Elements • Each square in the periodic table lists four pieces of information: an element’s atomic number, chemical symbol, name, and atomic mass.

• • 17 • F • Cl • Br • I • At

• Each Group is a family named vertically.

• Named by column Number or top element in the group, or

• a special name. • elements have similar properties like family members with same Bonding Power by Valence electrons

18 Basic Family Groups

• • Period (horizontal row) • A period tells the number of energy levels (shells, rings)

• members have same energy level, but different properties.

7 periods (rows)

• Draw this atom in NB 1. How many protons are

in this atom? 2. How many electrons

are in this atom? 3. How many energy

levels are shown in this atom?

4. In what period is this atom?

5. How many energy levels are in Period 5?

• • Every Family Group has the same Bonding Power in a chemical reaction.

• Chemical bonding is done by special electrons with the highest energy called Valence Electrons

• VE’s are located on the outside ring, farthest level from the nucleus, the highest energy level.

• Each Family Group has the same number of VE’s.

• For example, every member of the Carbon family has 4 valence electrons.

Bonding Power – Valence Electrons

4 valence electrons on the carbon atom

• • Number of valence electrons for each group matches the Group number.

• For example: Group 1 has one VE • Group 2 has 2 VE’s • (Skip over to Group 13 to follow the

pattern) • Group 13 has 3 VE’s. • Group 14 has 4 VE’s. • Group 15, 5 VE’s. • Group 16, 6 VE’s • Group 17, 7 VE’s • Group 18, 8 VE’s, (except He, 2 VE’s)

Bonding Power – Valence Electrons

• Quick Quiz: 6 questions. (with answers) • How many electrons? 7 (total) • How many VEs? 5 (on outside ring) • Which period? 2 (2 rings/energy levels) • Which group? 15 (5 VE’s) • What is the Atomic Number? 7 (Period 2, Group 15) • What is the name of this element? Nitrogen

Cfu Observe the diagram of this atomic model.

• Quick Quiz: 7 questions. • How many electrons? • How many VEs? • Which period? • Which group? • What is the Atomic Number? • What is the name of this element? • Pb is in the same family, compare their sizes, who’s larger? Why?

Cfu Observe the diagram of this atomic model.