8w2l1 The Atom Exploring Its Structure.pptx

What do you think makes up everything around us?"

An overview of the fundamental building blocks of matter, exploring the structure and composition of atoms.

The Atom: Exploring Its Structure

• Electron

A negatively charged particle that orbits the nucleus of an atom, playing a key role in chemical bonding.

• Isotope

Variants of a particular chemical element that have the same number of protons but different numbers of neutrons.

• Molecule

A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound.

• Atom

The basic unit of a chemical element, consisting of a nucleus surrounded by electrons.

• Nucleus

The central part of an atom that contains protons and neutrons, acting as the atom's core.

• Proton

A positively charged particle found in the nucleus of an atom, contributing to its mass and positive charge.

• Neutron

A particle found in the nucleus of an atom that has no charge, contributing to the atom's mass.

Thesaurus

In summary, elements are the fundamental building blocks of matter, with each element possessing its own unique set of properties and behaviors. The periodic table provides a comprehensive overview of the 118 known elements, allowing scientists to explore and understand the intricate nature of the atom.

The periodic table is a comprehensive chart that organizes all the known elements based on their atomic structure and chemical properties. It serves as a valuable tool for scientists and researchers.

118 known elements in the periodic table

These are some common examples of elements, each with their own unique properties and behaviors. Oxygen is a gas, gold is a metal, carbon is a solid, and hydrogen is the lightest element.

Examples: oxygen, gold, carbon, hydrogen

Elements are the fundamental building blocks of matter, consisting of a single type of atom that cannot be broken down further without changing its chemical properties.

Pure substances made of only one type of atom

The Atom: Exploring Its Structure

Understanding the structure and components of atoms is crucial for comprehending the fundamental nature of matter and the world around us.

Atoms are composed of protons (positive charge), neutrons (neutral charge), and electrons (negative charge).

Atoms are made up of even smaller particles

Atoms are approximately 1 x 10^-10 meters in diameter, making them almost impossible to see with the naked eye.

Atoms are incredibly tiny

Atoms are the fundamental building blocks of all matter, and they retain the properties of the element they represent.

Atoms are the smallest unit of an element

The Atom: Exploring Its Structure

By understanding the key components of the atom, we can better comprehend the building blocks of all matter in the universe.

Negatively charged particles that orbit the nucleus of the atom.

Electrons

Electrically neutral particles that also reside in the atom's nucleus.

Neutrons

Positively charged particles that make up the nucleus of the atom.

Protons

Welcome to the Atom!

Quantum mechanics provides a probabilistic description of the behavior of electrons within the atom.

1950s-1960s

Enrico Fermi and others explore the concept of nuclear fission, leading to the development of nuclear reactors and atomic bombs.

1938-1945

James Chadwick discovers the neutron, providing a more complete understanding of the atom's structure.

1932

Niels Bohr proposes a model of the atom with electrons orbiting the nucleus in specific energy levels.

1913

Ernest Rutherford's gold foil experiment reveals the existence of a dense, positively charged nucleus within the atom.

1911

J.J. Thomson discovers the electron, leading to a model of the atom as a positively charged sphere with negatively charged electrons embedded within.

1897

John Dalton develops the atomic theory, which describes atoms as solid, indivisible spheres.

1803

Democritus proposes the idea of the atom as the smallest indivisible unit of matter.

Ancient Greece

The Journey to Atomic Structure

The periodic table is a tabular arrangement of the chemical elements, organized based on their atomic structure and properties. It is a fundamental tool in chemistry, providing a wealth of information about the elements and their relationships.

The Periodic Table

The modern quantum mechanical model describes the atom as a probability distribution of electrons around the nucleus, where the exact position and momentum of electrons cannot be determined simultaneously.

Quantum Mechanical Model

In 1913, Niels Bohr refined Rutherford's model by introducing the concept of discrete energy levels for electrons, explaining the emission and absorption of specific wavelengths of light by atoms.

Bohr's Atomic Model

In 1911, Ernest Rutherford's gold foil experiment led to the discovery of the atomic nucleus, and he proposed a model where the atom consists of a dense, positively charged nucleus surrounded by orbiting electrons.

Rutherford's Nuclear Model

In 1904, J.J. Thomson proposed the plum pudding model, where the atom was described as a positively charged sphere with negatively charged electrons embedded within it.

Thomson's Plum Pudding Model

The ancient Greek philosopher Democritus proposed that matter is composed of indivisible particles called atoms, but this model lacked details on the internal structure of atoms.

Ancient Greek Model

Atomic Models

The protons and neutrons are located at the centre of the atom, which is called the nucleus The electrons move very fast around the nucleus in orbital paths called shells The size of atoms is so tiny that we can't really compare their masses in conventional units such as kilograms or grams, so a unit called the relative atomic mass is used One relative atomic mass unit is equal to 1/12th the mass of a carbon-12 atom.All other elements are measured relative to the mass of a carbon-12 atom, so relative atomic mass has no units  Hydrogen for example has a relative atomic mass of 1, meaning that 12 atoms of hydrogen would have exactly the same mass as 1 atom of carbon

Atomic Particles

*Data from the Atomic Mass Data Center: https://www-nds.iaea.org/amdc/

1.00866

Neutron

+1

1.00727

Proton

Charge (e)

Mass (u)

Particle

Atomic Masses and Charges

The atomic number is a fundamental property of an element, defining its identity and positioning on the Periodic Table.

The atomic number is the determining factor for the position of an element on the Periodic Table, as it dictates the element's chemical properties and behavior.

Periodic Table Position

The atomic number determines the number of protons in the nucleus of an atom, which is also the number of electrons in a neutral atom.

Protons in Nucleus

The atomic number, denoted by the symbol Z, is the number of protons in the nucleus of an atom.

Atomic Number

The Atom: Exploring Its Structure

The nucleon number, also known as the mass number, is the total number of protons and neutrons in the nucleus of an atom. It is represented by the symbol 'A' and is crucial in understanding the composition and properties of an element. The number of neutrons in an atom can be determined by subtracting the atomic number (the number of protons) from the nucleon number.

The Nucleon Number: Understanding Atomic Composition

By understanding how to deduce the number of protons, neutrons, and electrons in an atom or ion, we can determine the elemental composition and understand the atom's structure.

The mass and atomic numbers can be used to find the number of neutrons in ions and atoms: Number of neutrons = mass number - number of protons.

Finding Neutrons

An atom is neutral and therefore has the same number of protons and electrons.

Determining Electrons

Number of protons = mass number - number of neutrons.

Mass number = number of protons + number of neutrons,

The number of protons equals the atomic (proton) number. The number of protons of an unknown element can be calculated by using its mass number and number of neutrons:

Calculating Protons

The atomic number of an atom and ion determines which element it is. All atoms and ions of the same element have the same number of protons (atomic number) in the nucleus.

Atomic Number Determines Element

The Atom: Exploring Its Structure

• Number of Electrons

Since the atom is electrically neutral, the number of electrons in the atom of element X is also ___, equal to the number of protons.

• Number of Neutrons

To calculate the number of neutrons, we subtract the atomic number from the mass number, which gives us 63 - 29 = ____ neutrons in the nucleus of the atom of element X.

• Atomic Number

The atomic number of element X is 29, which represents the number of protons in the nucleus of the atom.

• Mass Number

The mass number of element X is 63, which represents the total number of protons and neutrons in the nucleus of the atom.

• Number of Protons

Since the atomic number is 29, the element X has ____ protons in the nucleus of the atom.

The Atom: Exercise

Analyze how the arrangement of elements in the periodic table reflects the periodic trends in atomic size, electronegativity, and ionization energy.

Periodic Trends

Investigate the different shapes and energy levels of atomic orbitals, and how they influence the distribution of electrons within an atom.

Atomic Orbitals

Discover the role of valence electrons in defining the chemical behavior and bonding abilities of atoms.

Valence Electrons

Explore the arrangement of electrons around the nucleus, and how this affects the reactivity and stability of different elements.

Electron Configurations

Understand how the number of protons, neutrons, and electrons in an atom determines its chemical identity and unique properties.

Atomic Composition

Atomic Configurations