The Periodic Table (But No Chairs) Ms. Donis

Chemistry

History of the Periodic Table ● https://www.youtube.com/watch?v=0RRVV

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History of the Periodic Table ● The periodic table took over 100 years to

develop:

○ Dmitri Mendeleev (Father of the

Periodic Table): created the first

periodic table, ordering ~60 elements

by atomic weight. However, a

limitation of his model was that it was

missing many elements

History of the Periodic Table ● Other scientists also contributed to the development of the

modern periodic table:

○ John Newlands: also arranged elements by increasing

atomic mass

○ Lothar Meyer : demonstrated a connection between

atomic mass and elements’ properties (periodicity)

○ Henry Moseley: discovered that atoms of each element

contain a unique number of protons, and thus a unique

atomic number.

The Periodic Table Chemists (and other scientists)

like to classify things based on

their similarities and the

properties that they share.

The term periodicity refers to a

pattern of repeating order,

where elements are arranged

by repeating patterns of

physical & chemical properties.

Patterns of Periodicity ● Elements are arranged in

order by increasing atomic

number.

● Elements are arranged in

order by increasing atomic

mass.

Classification of Elements (Periods + Families) The periodic table is made

of horizontal rows called

periods. They are

numbered 1-7.

Atomic Numbers increase

from left to right in each

of the periods

Classification of Elements (Periods + Families) The vertical columns are

called groups or families.

There are 18

groups/families.

Members of the same

family have similar

properties.

Important Groups/FamiliesFamily Names:

Red: Alkali Metals

● Group 1 or 1A

● Very unstable and

highly reactive

Important Groups/FamiliesOrange: Alkaline Earth Metals

● Group 2 or 2A

● Very reactive

Dark Blue: Halogens

● Group 17 or 7A

● Will easily bond with a metal

to form a compound.

Important Groups/FamiliesPurple: Noble Gases

● Group 18 or 8A

● They are the most stable group in

the Periodic Table, and non-reactive

● Also called inert gases, because they

do not react

● High densities, high melting points,

odorless, colorless and tasteless

Classification of Elements (Valence Electrons) Valence Electrons: Each

Group/Family is arranged

by the number of valence

electrons they contain.

Ex: Sodium(Na) has 1

valence electron

Ex: Bromine (Br) has 7

valence electrons

Concept Check #1How many valence electrons do the following atoms contain?

- Barium (Ba)

- Tin (Sn)

- Oxygen (O)

Classification of Elements (Metals, Nonmetals & Metalloids) Most of the elements in the periodic table are

considered metals.. They are located on the left

hand side of the periodic table.

Properties of metals:

1. Solid at room temperature

2. Shiny

3. Ductile (can be drawn into thin wires)

4. Malleable (can be easily hammered into thin

sheets)

5. They are good conductors of heat + electricity

Classification of Elements (Metals, Nonmetals & Metalloids) Nonmetals are those to the right of the periodic table. (EXCEPT FOR

HYDROGEN)

Properties of nonmetals:

1. Brittle

2. Not shiny

3. Most are gases at room temperature

4. Not Ductile

5. Not Malleable

6. Poor conductors of heat + electricity

Classification of Elements (Metals, Nonmetals & Metalloids) Metalloids/Semimetals: have

properties that cross between

metals and nonmetals.

Properties of metalloids:

1. Partially conduct electricity

Concept Check #2 Label each of the following elements as Metals, Nonmetals or

Metalloids:

1. Hydrogen

2. Carbon

3. Oxygen

4. Uranium

The inner

transition

metals are a

continuation of

the table. The

Lanthanide

Series belongs

in Period 6. The

Actinide Series

in Period 7

Periodic Trends : Atomic Radius Atomic Radius refers to the half the distance between 2 adjacent

atoms. (ie. defines how closely an atom lies to a neighboring

atom)

Periodic Trends : Atomic Radius

Periodic Trends : Ionization Energy Ionization Energy: the energy required to remove an electron

from a neutral atom.

Ionization Energy is an indication of how strongly an atom’s

nucleus holds to its electrons.

As the atom gets bigger, it is easier to remove an electron and

thus, the ionization energy decreases.

Periodic Trends: Electronegativity Electronegativity: refers to the ability of an atom to attract

electrons in a chemical bond.

**Ionization Energy/ Electronegativity have the same trend.

Concept Check #3 Indicate whether Fluorine or Bromine has a larger value of each

of the following properties:

a) Electronegativity

b) Atomic Radius

c) Ionization Energy