Review for CA2

Periodic Table

Group (column): 1-18

Period (row): 1-7

Elements are arranged in order of increasing atomic number

Properties

Exploring the Periodic Table

• Periodic Table: Arranged in order of increasing atomic number

• Group: Elements in the same group have same chemical properties

• Period: Elements arranged in rows from 1-7

• Bohr Diagram: Visual representation of an atom's electron arrangement

• Valence Electron: Electrons in the outermost energy level

• Lewis Dot Structure: Diagram showing valence electrons as dots around the element symbol

​Bohr model, description of the structure of atoms proposed in 1913 by the Danish physicist Niels Bohr.

​Bohr Diagram

​Valence Electrons

Group Number: 1-18

Group (Number + Letter): 1A, 2A….: Valence Electrons

​Ink-Pair-Share

Lewis Dot Structure

Lewis Dot Structure is a diagram that shows the valence electrons as dots around the element symbol. It is a simple and visual way to represent the electron arrangement in an atom. By using Lewis Dot Structures, chemists can easily determine the number of valence electrons and predict the chemical behavior of elements.

Response Card

Draw the Lewis dot structure for the following elements:

Oxygen, Phosphorus, Calcium

Atomic Theories and Periodic Table

• Democritus and the Idea of the Atom: Democritus proposed the concept of the atom as the fundamental unit of matter. He believed atoms were eternal, homogeneous, and in constant motion.
• J.J. Thomson and the Discovery of the Electron: Thomson discovered the electron through his experiments with cathode rays.

Democritus and the Atom

Did you know? Democritus, an ancient Greek philosopher, proposed the concept of the atom as the fundamental unit of matter. He believed that atoms were indivisible and indestructible. This idea laid the foundation for modern atomic theory, revolutionizing our understanding of the physical world.

The Evolution of Atomic Models

1. J.J. Thomson's Plum Pudding Model: Proposed that electrons are embedded in a positively charged 'soup' of matter.
2. Ernest Rutherford's Gold Foil Experiment: Discovered the mostly empty space of the atom with a small, dense nucleus at its center.
3. Niels Bohr's Quantum Model: Introduced energy levels and revolutionized our understanding of atomic structure.

​Response Card

What similarities exist between the Bohr model and the structure of our solar system?

Exploring the Periodic Table

Dmitri Mendeleev created the first periodic table in 1869. He organized elements based on atomic mass and chemical properties, leaving gaps for undiscovered elements. This method helps predict properties of undiscovered elements. Mendeleev's work laid the foundation for the modern periodic table.

Dmitri Mendeleev

Dmitri Mendeleev created the first periodic table in 1869. His table organized the elements based on their atomic mass and predicted the existence of undiscovered elements (Physical and chemical properties). Mendeleev's periodic table laid the foundation for our understanding of the elements and their properties. It is considered one of the most significant achievements in the field of chemistry.

​Response Card

After Mendeleev constructed the periodic table, he predicted the discovery of several elements that were not yet known. What prediction was Mendeleev able to make about these unknown elements, based on his table?

Quiz