Chemistry Chapter 3.1 Electron Theory

Study Notes

Matter and Elements

Matter is anything that occupies space and has weight, e.g., air, water, clothing, animals, and the human body.
Matter exists in three states: solid, liquid, and gaseous.
An element is a substance that cannot be broken down into simpler substances, such as gold, silver, oxygen, and iron.
Over 100 known elements combine to form various compounds encountered in daily life.
Compounds are formed when one or more elements chemically combine (e.g., salt is sodium and chlorine, water is hydrogen and oxygen).

Structure of the Atom

Atoms are the smallest particles that represent the characteristics of elements.
Each atom is composed of electrons, protons, and sometimes neutrons, known as sub-atomic particles.
The identity of an atom is determined by the number and arrangement of its sub-atomic particles.
Protons have a positive charge, electrons have a negative charge, and neutrons are neutral, with protons being significantly more massive than electrons.
The atomic nucleus contains protons and neutrons, while electrons orbit around the nucleus.
Elements are classified by atomic number, which is the number of protons: hydrogen (atomic number 1) and helium (atomic number 2).
Neutral atoms have an equal number of protons and electrons, resulting in no overall charge.

Molecules

The smallest unit of a substance retaining its chemical properties is called a molecule.
Molecules are composed of two or more atoms; elements can consist of identical atoms, such as a diatomic oxygen molecule (O₂).
Compounds consist of different types of atoms, like a water molecule (H₂O) made of one oxygen and two hydrogen atoms.

Energy Levels

Electrons occupy orbits around the nucleus, defined as shells that correspond to specific energy levels.
Under normal conditions, electrons fill the lowest energy shell available.
When energized, electrons can jump to higher energy shells; however, this state is temporary.
As electrons return to their original shells, they release energy, illustrating the relationship between electron movement and energy.

Key Concepts

Atoms and molecules are foundational to the diversity of matter in nature.
The interaction and combination of sub-atomic particles dictate the properties and classifications of elements and compounds.
Understanding atomic structure and energy dynamics provides insight into the behavior of matter on a molecular level.

Description

Explore the fundamental concepts of Electron Theory in this quiz from Chemistry Chapter 3.1. You'll learn about the structure and distribution of electrical charges in atoms, molecules, ions, and compounds, and how these relate to the states of matter and elements. Test your understanding of matter's properties with engaging questions.