Now remember, an atom possesses shells. Each shell for a given atom has a maximum number of electrons it can hold. So here, when only the shell number n is given, the number of electrons is equal to 2×n2. So, if we're looking here at the first shell where n=1, that would mean that we have 2×12, which is 2×1, so the first shell can hold a maximum of 2 electrons. The second shell here, n=2, that'd be 2×22, which would be 2×4, which equals 8 electrons max that it can hold. So remember, if they only give you the n value, then you can use 2×n2 to determine the total number of electrons found within that given shell.

- 1. The Chemical World9m
- 2. Measurement and Problem Solving2h 25m
- 3. Matter and Energy2h 15m
- Classification of Matter18m
- States of Matter8m
- Physical & Chemical Changes19m
- Chemical Properties8m
- Physical Properties5m
- Temperature (Simplified)9m
- Law of Conservation of Mass5m
- Nature of Energy5m
- First Law of Thermodynamics7m
- Endothermic & Exothermic Reactions7m
- Heat Capacity16m
- Thermal Equilibrium (Simplified)8m
- Intensive vs. Extensive Properties13m

- 4. Atoms and Elements2h 33m
- The Atom (Simplified)9m
- Subatomic Particles (Simplified)12m
- Isotopes17m
- Ions (Simplified)22m
- Atomic Mass (Simplified)17m
- Periodic Table: Element Symbols6m
- Periodic Table: Classifications11m
- Periodic Table: Group Names8m
- Periodic Table: Representative Elements & Transition Metals7m
- Periodic Table: Phases (Simplified)8m
- Periodic Table: Main Group Element Charges12m
- Atomic Theory9m
- Rutherford Gold Foil Experiment9m

- 5. Molecules and Compounds1h 50m
- Law of Definite Proportions9m
- Periodic Table: Elemental Forms (Simplified)6m
- Naming Monoatomic Cations6m
- Naming Monoatomic Anions5m
- Polyatomic Ions25m
- Naming Ionic Compounds11m
- Writing Formula Units of Ionic Compounds7m
- Naming Acids18m
- Naming Binary Molecular Compounds6m
- Molecular Models4m
- Calculating Molar Mass9m

- 6. Chemical Composition1h 23m
- 7. Chemical Reactions1h 43m
- 8. Quantities in Chemical Reactions1h 16m
- 9. Electrons in Atoms and the Periodic Table2h 32m
- Wavelength and Frequency (Simplified)5m
- Electromagnetic Spectrum (Simplified)11m
- Bohr Model (Simplified)9m
- Emission Spectrum (Simplified)3m
- Electronic Structure4m
- Electronic Structure: Shells5m
- Electronic Structure: Subshells4m
- Electronic Structure: Orbitals11m
- Electronic Structure: Electron Spin3m
- Electronic Structure: Number of Electrons4m
- The Electron Configuration (Simplified)20m
- The Electron Configuration: Condensed4m
- Ions and the Octet Rule9m
- Valence Electrons of Elements (Simplified)5m
- Periodic Trend: Metallic Character4m
- Periodic Trend: Atomic Radius (Simplified)7m
- Periodic Trend: Ionization Energy (Simplified)9m
- Periodic Trend: Electron Affinity (Simplified)7m
- Electron Arrangements5m
- The Electron Configuration: Exceptions (Simplified)12m

- 10. Chemical Bonding2h 10m
- Lewis Dot Symbols (Simplified)7m
- Ionic Bonding6m
- Covalent Bonds6m
- Lewis Dot Structures: Neutral Compounds (Simplified)8m
- Bonding Preferences6m
- Multiple Bonds4m
- Lewis Dot Structures: Multiple Bonds10m
- Lewis Dot Structures: Ions (Simplified)8m
- Lewis Dot Structures: Exceptions (Simplified)12m
- Resonance Structures (Simplified)5m
- Valence Shell Electron Pair Repulsion Theory (Simplified)4m
- Electron Geometry (Simplified)7m
- Molecular Geometry (Simplified)9m
- Bond Angles (Simplified)11m
- Dipole Moment (Simplified)14m
- Molecular Polarity (Simplified)7m

- 11 Gases2h 15m
- 12. Liquids, Solids, and Intermolecular Forces1h 11m
- 13. Solutions3h 1m
- 14. Acids and Bases2h 14m
- 15. Chemical Equilibrium1h 27m
- 16. Oxidation and Reduction1h 33m
- 17. Radioactivity and Nuclear Chemistry53m

# Electronic Structure: Number of Electrons - Online Tutor, Practice Problems & Exam Prep

An atom has electron shells, each with a maximum capacity determined by the formula ${2}^{\left(n\right)^2}$. For the first shell (n=1), it holds 2 electrons, while the second shell (n=2) can hold 8 electrons. Understanding these limits is crucial for grasping atomic structure and electron configuration, which are foundational concepts in chemistry.

Shell number can give the quantity of electrons within a given atom.

## Number of Electrons within a Shell

### Electronic Structure: Number of Electrons Concept 1

#### Video transcript

### Electronic Structure: Number of Electrons Example 1

#### Video transcript

Here we have to determine how many electrons can be found in the 7th shell of an atom. So remember, the 7th shell corresponds to n equals 7. When we only know the shell number, the number of electrons is just equal to:

E = 2 ∙ n 2So that will equal 2 ∙ 72. 7 squared is 49, and multiplying it by 2 means that we can have theoretically up to 98 electrons within the 7th shell of a given atom. So that would mean that option d would be our correct answer.

Theoretically, how many total electrons can be found in the 6th shell of an atom?

An element possesses 4 energy levels. How many total electrons can it theoretically hold?

### Here’s what students ask on this topic:

How do you determine the maximum number of electrons in an electron shell?

The maximum number of electrons in an electron shell can be determined using the formula $2{n}^{2}$, where $n$ is the principal quantum number of the shell. For example, for the first shell ($n=1$), the maximum number of electrons is $2{1}^{2}=2$. For the second shell ($n=2$), it is $2{2}^{2}=8$. This formula helps in understanding the electron configuration and the structure of atoms.

What is the electron capacity of the second shell in an atom?

The electron capacity of the second shell in an atom can be calculated using the formula $2{n}^{2}$. For the second shell, $n=2$. Therefore, the maximum number of electrons it can hold is $2{2}^{2}=8$. This means the second shell can accommodate up to 8 electrons.

Why is the formula 2(n)^2 used to determine the number of electrons in a shell?

The formula $2{n}^{2}$ is used to determine the number of electrons in a shell because it accounts for the quantum mechanical principles governing electron distribution. The principal quantum number $n$ indicates the shell level, and the formula considers both the number of orbitals in a shell and the Pauli exclusion principle, which states that each orbital can hold a maximum of two electrons. This formula helps in understanding the electron configuration and the structure of atoms.

How many electrons can the first shell of an atom hold?

The first shell of an atom, where the principal quantum number $n=1$, can hold a maximum of 2 electrons. This is determined using the formula $2{n}^{2}$. For $n=1$, the calculation is $2{1}^{2}=2$. This means the first shell can accommodate up to 2 electrons.

What is the significance of the principal quantum number (n) in determining electron capacity?

The principal quantum number ($n$) is significant in determining electron capacity because it indicates the energy level or shell of an atom. The formula $2{n}^{2}$ uses $n$ to calculate the maximum number of electrons that can occupy a given shell. For example, for $n=1$, the first shell can hold 2 electrons, and for $n=2$, the second shell can hold 8 electrons. This helps in understanding the electron configuration and the structure of atoms.