How To Calculate The Number of Protons, Neutrons, and Electrons - Chemistry

The Organic Chemistry Tutor
8 Sept 201813:12
EducationalLearning
32 Likes 10 Comments

TLDRThis educational video script explains the process of calculating the number of protons, neutrons, and electrons in an atom or ion, using sodium as a primary example. It details how the atomic number equals the number of protons and how the mass number relates to the number of neutrons. The script further clarifies the relationship between electrons and the charge of an ion or atom, providing clear formulas for determining these fundamental components of matter.

Takeaways
  • 🌟 The atomic number represents the number of protons and is unique to each element, determining its identity.
  • 🔬 The average atomic mass on the periodic table is the weighted average of all isotopes of an element found on Earth.
  • 📊 The mass number of an isotope is indicated when written as a superscript to the left of the element symbol, showing its specific form.
  • 🤔 To calculate the number of neutrons, subtract the atomic number from the mass number.
  • 💡 For a neutral atom, the number of electrons equals the atomic number, maintaining electrical neutrality.
  • 🔋 For ions, the number of electrons differs from the number of protons due to the charge, with cations having fewer electrons than protons and anions the opposite.
  • 🧠 The most abundant isotope of an element on Earth is the one closest to its average atomic mass.
  • 📐 For an ion with a given charge and known number of neutrons and electrons, the atomic number can be determined by using the electron formula.
  • 🔍 Once the atomic number is known, the element can be identified using the periodic table.
  • 🌠 Sodium, aluminum, and silicon are used as examples to illustrate the calculation of protons, neutrons, and electrons.
  • 💡🔋 A positively charged ion (cation) will have more protons than electrons, while a negatively charged ion (anion) will have more electrons than protons.
Q & A

  • What is the atomic number of sodium and how does it relate to the number of protons in the element?

    -The atomic number of sodium is 11. It is equal to the number of protons in the element, meaning sodium always has 11 protons.

  • How is the average atomic mass of an element determined?

    -The average atomic mass of an element is determined by averaging all of the isotopes of that element found on Earth.

  • What is the most abundant isotope of sodium on Earth and why is it significant?

    -The most abundant isotope of sodium on Earth is sodium-23. It is significant because it has the highest natural occurrence and is also the most stable form of sodium found on Earth.

  • How can you calculate the number of neutrons in an atom?

    -You can calculate the number of neutrons in an atom by subtracting the atomic number from the mass number.

  • What is the relationship between the charge of an ion and the number of electrons it has?

    -For a cation (positively charged ion), the number of electrons is less than the number of protons by the magnitude of the charge. For an anion (negatively charged ion), the number of electrons is more than the number of protons by the magnitude of the charge.

  • How does the number of protons, neutrons, and electrons differ between an atom and an ion?

    -In an atom, the number of protons equals the number of electrons, making it electrically neutral. In ions, the number of electrons differs from the number of protons based on the charge of the ion.

  • What is the atomic number of aluminum and how does it relate to the number of protons and electrons in a neutral aluminum atom?

    -The atomic number of aluminum is 13. In a neutral aluminum atom, the number of protons and electrons is equal to the atomic number, which is 13.

  • How can you find the atomic number of an element if you know the number of electrons and the charge of the ion?

    -You can find the atomic number of an element by adding the charge to the number of electrons (for cations) or subtracting the absolute value of the charge from the number of electrons (for anions), since the number of electrons equals the atomic number minus the charge.

  • What is the mass number of silicon-29 and how can you determine it?

    -The mass number of silicon-29 is 29. It is indicated directly in the notation 'silicon-29', where the number represents the mass number.

  • How can you identify an unknown element with a given number of neutrons, electrons, and charge?

    -You can identify an unknown element by first using the number of electrons and the charge to calculate the atomic number (electrons plus charge for cations or electrons minus charge for anions). Once you have the atomic number, you can look up the element on the periodic table.

  • What is the relationship between the mass number, atomic number, and the number of neutrons in an element?

    -The mass number of an element is the sum of its atomic number (protons) and the number of neutrons (mass number minus atomic number).

  • How can you calculate the number of electrons in a neutral atom?

    -In a neutral atom, the number of electrons is equal to the atomic number, as the atom has no net charge.

Outlines
00:00
🌟 Understanding Atomic Structure: Sodium Example

This paragraph introduces the concept of calculating the number of protons, neutrons, and electrons in an atom or ion, using sodium as an example. It explains the atomic number and average atomic mass, differentiating between isotopes and highlighting the most abundant and stable isotope of sodium. The paragraph emphasizes that the atomic number is key to an element's identity, with the mass number varying among isotopes. It outlines the formulas needed to calculate the atomic structure, focusing on the relationship between the number of protons, neutrons, and electrons in neutral atoms versus charged ions.

05:03
🔬 Calculating Atomic Components: Aluminum and Sulfide Ions

The second paragraph delves into the calculation of protons, neutrons, and electrons for different ions, using aluminum with a +3 charge and the sulfide ion with a -2 charge as examples. It illustrates how the charge affects the number of electrons in relation to protons, resulting in different quantities for cations and anions. The paragraph also introduces a method for determining the atomic structure of silicon-29, emphasizing the use of the periodic table to identify the atomic number when not directly provided.

10:06
💡 Solving the Challenge: Identifying Unknown Elements

The final paragraph presents a challenge problem involving an unknown cation with a +4 charge, 26 neutrons, and 18 electrons. It guides the viewer through the process of identifying the element by using the number of electrons to determine the atomic number, and then using that information to find the element on the periodic table. The solution reveals that the unknown element is titanium, demonstrating how understanding atomic structure and ion charges can lead to the identification of any unknown element.

Mindmap
Keywords
💡atomic number
The atomic number is a fundamental property of an element that defines its identity on the periodic table. It represents the number of protons in the nucleus of an atom and is unique for each element. In the context of the video, the atomic number is used to determine the element's identity and is always equal to the number of protons. For example, sodium has an atomic number of 11, which means it has 11 protons.
💡protons
Protons are subatomic particles found in the nucleus of an atom and carry a positive electric charge. The number of protons in an atom determines the element's identity and is referred to as the atomic number. In the video, the number of protons is a key factor in identifying an element and calculating the composition of atoms and ions.
💡neutrons
Neutrons are subatomic particles that, like protons, reside in the nucleus of an atom but do not carry any electric charge. The number of neutrons, combined with the number of protons (atomic number), determines the isotope of an element. In the context of the video, the number of neutrons is calculated by subtracting the atomic number from the mass number of an isotope.
💡electrons
Electrons are negatively charged subatomic particles that orbit the nucleus of an atom. The number of electrons in a neutral atom is equal to the number of protons, balancing the positive charge. However, in ions, the number of electrons differs from the number of protons based on the charge of the ion. The video emphasizes the relationship between the atomic number, charge, and number of electrons in determining the composition of atoms and ions.
💡isotopes
Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number, but not in proton number. All isotopes of an element have the same number of protons but different numbers of neutrons, resulting in different mass numbers. The video explains that sodium has several isotopes, with sodium-23 being the most abundant and stable on Earth.
💡mass number
The mass number of an atom or molecule is the sum of the number of protons and neutrons in its nucleus. It is often used to differentiate between isotopes of the same element, which have the same atomic number but different mass numbers. In the video, the mass number is used to calculate the number of neutrons and to identify isotopes.
💡ions
Ions are atoms or molecules that have a net electric charge due to the loss or gain of one or more electrons. The type of ion (cation or anion) and the magnitude of its charge are determined by the difference between the number of protons and electrons. In the video, ions are discussed in relation to their charge and how it affects the number of electrons compared to protons.
💡atomic mass
The atomic mass is the mass of an atom, typically measured in atomic mass units (amu). It is the weighted average of the masses of all isotopes of an element as they occur naturally. The atomic mass is different from the mass number, as it accounts for the relative abundance of each isotope. The video clarifies the difference between atomic mass and mass number, especially when discussing elements like sodium.
💡electrically neutral atoms
Electrically neutral atoms are atoms in which the number of protons (positive charges) is equal to the number of electrons (negative charges), resulting in no net electric charge. This balance is essential for the stable existence of atoms under normal conditions. The video emphasizes that in neutral atoms, the number of protons and electrons are the same.
💡charge
In the context of atoms and ions, charge refers to the net electric charge an atom or ion carries due to the imbalance between the number of protons and electrons. A positive charge indicates more protons than electrons, while a negative charge indicates more electrons than protons. The charge affects the number of electrons in ions and is a crucial factor in chemical reactions and bonding.
💡periodic table
The periodic table is a tabular arrangement of the chemical elements, organized by increasing atomic number and grouped by common properties. It is a fundamental tool in chemistry for predicting the behavior of elements and their compounds. The video uses the periodic table to identify elements by their atomic numbers and to find the atomic number of silicon when solving a problem.
Highlights

The lesson focuses on calculating the number of protons, neutrons, and electrons in an atom and ion.

Sodium is used as an example to illustrate the concepts.

The atomic number represents the number of protons and is equal to the charge of the species.

The average atomic mass represents the weighted average of all isotopes of an element.

Sodium-23 is the most abundant and stable isotope on Earth.

The identity of an element is determined by its atomic number, which is constant across isotopes.

The number of protons is always equal to the atomic number.

The number of neutrons is calculated by subtracting the atomic number from the mass number.

For an atom, the number of electrons equals the atomic number, maintaining electrical neutrality.

In ions, the number of electrons differs from the number of protons due to the charge.

Positively charged cations have more protons than electrons, while negatively charged anions have more electrons than protons.

The number of protons and electrons in an atom are the same because atoms are electrically neutral.

To find the atomic number of an ion, use the formula relating electrons, charge, and atomic number.

Once the atomic number is known, the element can be identified using the periodic table.

The mass number of an ion can be found by adding the number of neutrons to the number of protons.

The example of aluminum-27 with a three positive charge is used to demonstrate the calculation of protons, neutrons, and electrons in an ion.

The sulfide ion example shows how to calculate the number of protons, neutrons, and electrons for a negatively charged ion.

Silicon-29 is used as an example to illustrate how to determine the atomic number when it's not directly provided.

A challenge problem involving a cation with a four positive charge, 26 neutrons, and 18 electrons is solved to identify the element as titanium.

Transcripts

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Atomic StructureChemistry BasicsElemental IdentityIsotopesPeriodic TableQuantum MechanicsSodium ExamplesAluminum IonsEducational ContentScientific Calculations